1
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Cohen IJ, Smith EJ, Clark GB, Turner DL, Ellison DH, Clare B, Regoli LH, Kollmann P, Gallagher DT, Holtzman GA, Likar JJ, Morizono T, Shannon M, Vodusek KS. Plasma Environment, Radiation, Structure, and Evolution of the Uranian System (PERSEUS): A Dedicated Orbiter Mission Concept to Study Space Physics at Uranus. Space Sci Rev 2023; 219:65. [PMID: 37869526 PMCID: PMC10587260 DOI: 10.1007/s11214-023-01013-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/05/2023] [Indexed: 10/24/2023]
Abstract
The Plasma Environment, Radiation, Structure, and Evolution of the Uranian System (PERSEUS) mission concept defines the feasibility and potential scope of a dedicated, standalone Heliophysics orbiter mission to study multiple space physics science objectives at Uranus. Uranus's complex and dynamic magnetosphere presents a unique laboratory to study magnetospheric physics as well as its coupling to the solar wind and the planet's atmosphere, satellites, and rings. From the planet's tilted and offset, rapidly-rotating non-dipolar magnetic field to its seasonally-extreme interactions with the solar wind to its unexpectedly intense electron radiation belts, Uranus hosts a range of outstanding and compelling mysteries relevant to the space physics community. While the exploration of planets other than Earth has largely fallen within the purview of NASA's Planetary Science Division, many targets, like Uranus, also hold immense scientific value and interest to NASA's Heliophysics Division. Exploring and understanding Uranus's magnetosphere is critical to make fundamental gains in magnetospheric physics and the understanding of potential exoplanetary systems and to test the validity of our knowledge of magnetospheric dynamics, moon-magnetosphere interactions, magnetosphere-ionosphere coupling, and solar wind-planetary coupling. The PERSEUS mission concept study, currently at Concept Maturity Level (CML) 4, comprises a feasible payload that provides closure to a range of space physics science objectives in a reliable and mature spacecraft and mission design architecture. The mission is able to close using only a single Mod-1 Next-Generation Radioisotope Thermoelectric Generator (NG-RTG) by leveraging a concept of operations that relies of a significant hibernation mode for a large portion of its 22-day orbit.
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Affiliation(s)
- Ian J Cohen
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Evan J Smith
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - George B Clark
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Drew L Turner
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Donald H Ellison
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Ben Clare
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Leonardo H Regoli
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Peter Kollmann
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | | | - G Allan Holtzman
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Justin J Likar
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Takeshi Morizono
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Matthew Shannon
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
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2
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Kitamura N, Amano T, Omura Y, Boardsen SA, Gershman DJ, Miyoshi Y, Kitahara M, Katoh Y, Kojima H, Nakamura S, Shoji M, Saito Y, Yokota S, Giles BL, Paterson WR, Pollock CJ, Barrie AC, Skeberdis DG, Kreisler S, Le Contel O, Russell CT, Strangeway RJ, Lindqvist PA, Ergun RE, Torbert RB, Burch JL. Direct observations of energy transfer from resonant electrons to whistler-mode waves in magnetosheath of Earth. Nat Commun 2022; 13:6259. [PMID: 36307443 PMCID: PMC9616889 DOI: 10.1038/s41467-022-33604-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 09/22/2022] [Indexed: 11/30/2022] Open
Abstract
Electromagnetic whistler-mode waves in space plasmas play critical roles in collisionless energy transfer between the electrons and the electromagnetic field. Although resonant interactions have been considered as the likely generation process of the waves, observational identification has been extremely difficult due to the short time scale of resonant electron dynamics. Here we show strong nongyrotropy, which rotate with the wave, of cyclotron resonant electrons as direct evidence for the locally ongoing secular energy transfer from the resonant electrons to the whistler-mode waves using ultra-high temporal resolution data obtained by NASA’s Magnetospheric Multiscale (MMS) mission in the magnetosheath. The nongyrotropic electrons carry a resonant current, which is the energy source of the wave as predicted by the nonlinear wave growth theory. This result proves the nonlinear wave growth theory, and furthermore demonstrates that the degree of nongyrotropy, which cannot be predicted even by that nonlinear theory, can be studied by observations. Excitation of whistler-mode waves by cyclotron instability is considered as the likely generation process of the waves. Here, the authors show direct observational evidence for locally ongoing secular energy transfer from the resonant electrons to the whistler-mode waves in Earth’s magnetosheath.
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Affiliation(s)
- N Kitamura
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan. .,Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Tokyo, Japan.
| | - T Amano
- Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Y Omura
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - S A Boardsen
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,Goddard Planetary Heliophysics Institute, University of Maryland, Baltimore County, MD, USA
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Y Miyoshi
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
| | - M Kitahara
- Department of Geophysics, Graduate school of Science, Tohoku University, Sendai, Japan
| | - Y Katoh
- Department of Geophysics, Graduate school of Science, Tohoku University, Sendai, Japan
| | - H Kojima
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - S Nakamura
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
| | - M Shoji
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
| | - Y Saito
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
| | - S Yokota
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | - A C Barrie
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,Aurora Engineering, Potomac, MD, USA
| | - D G Skeberdis
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,a.i. solutions Inc, Lanham, MD, USA
| | - S Kreisler
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,Aurora Engineering, Potomac, MD, USA
| | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS/Sorbonne Université/Université Paris-Saclay/Observatoire de Paris/Ecole Polytechnique Institut Polytechnique de Paris, Paris, France
| | - C T Russell
- Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA
| | - R J Strangeway
- Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA
| | | | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - R B Torbert
- Department of Physics, University of New Hampshire, Durham, NH, USA.,Southwest Research Institute, San Antonio, TX, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, TX, USA
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3
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George H, Reeves G, Cunningham G, Kalliokoski MMH, Kilpua E, Osmane A, Henderson MG, Morley SK, Hoilijoki S, Palmroth M. Contributions to Loss Across the Magnetopause During an Electron Dropout Event. J Geophys Res Space Phys 2022; 127:e2022JA030751. [PMID: 36591320 PMCID: PMC9787648 DOI: 10.1029/2022ja030751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 06/17/2023]
Abstract
Dropout events are dramatic decreases in radiation belt electron populations that can occur in as little as 30 minutes. Loss to magnetopause due to a combination of magnetopause shadowing and outward radial transport plays a significant role in these events. We examine the dropout of relativistic electron populations during the October 2012 geomagnetic storm using simulated electron phase space density, evaluating the contribution of different processes to losses across the magnetopause. We compare loss contribution from outward transport calculated using a standard empirical radial diffusion model that assumes a dipolar geomagnetic field to an event-specific radial diffusion model evaluated with a non-dipolar geomagnetic field. We additionally evaluate the contribution of Shabansky type 1 particles, which bounce along magnetic field lines with local equatorial maxima, to the loss calculated during this event. We find that the empirical radial diffusion model with a dipolar background field underestimates the contribution of radial diffusion to this dropout event by up to 10% when compared to the event-specific, non-dipolar radial diffusion model. We additionally find that including Shabansky type 1 particles in the initial electron phase space density, that is, allowing some magnetic field lines distorted from the typical single-minima configuration in drift shell construction, increases the calculated loss by an average of 0.75%. This shows that the treatment of the geomagnetic field significantly impacts the calculation of electron losses to the magnetopause during dropout events, with the non-dipolar treatment of radial diffusion being essential to accurately quantify the loss of outer radiation belt populations.
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Affiliation(s)
- H. George
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - G. Reeves
- Intelligence and Space Research DivisionLos Alamos National LaboratoryLos AlamosNMUSA
| | - G. Cunningham
- Intelligence and Space Research DivisionLos Alamos National LaboratoryLos AlamosNMUSA
| | | | - E. Kilpua
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - A. Osmane
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. G. Henderson
- Intelligence and Space Research DivisionLos Alamos National LaboratoryLos AlamosNMUSA
| | - S. K. Morley
- Intelligence and Space Research DivisionLos Alamos National LaboratoryLos AlamosNMUSA
| | - S. Hoilijoki
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Palmroth
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
- Space and Earth Observation CenterFinnish Meteorological InstituteHelsinkiFinland
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4
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Song P, Tu J, Galkin IA, McCollough JP, Ginet GP, Johnston WR, Su YJ, Starks MJ, Reinisch BW, Inan US, Lauben DS, Linscott IR, Farrell WM, Allgeier S, Lambour R, Schoenberg J, Gillespie W, Stelmash S, Roche K, Sinclair AJ, Sanchez JC. Discovery and insights from DSX mission's high-power VLF wave transmission experiments in the radiation belts. Sci Rep 2022; 12:14304. [PMID: 35995921 DOI: 10.1038/s41598-022-18542-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/16/2022] [Indexed: 11/23/2022] Open
Abstract
Space weather phenomena can threaten space technologies. A hazard among these is the population of relativistic electrons in the Van Allen radiation belts. To reduce the threat, artificial processes can be introduced by transmitting very-low-frequency (VLF) waves into the belts. The resulting wave-particle interactions may deplete these harmful electrons. However, when transmitting VLF waves in space plasma, the antenna, plasma, and waves interact in a manner that is not well-understood. We conducted a series of VLF transmission experiments in the radiation belts and measured the power and radiation impedance under various frequencies and conditions. The results demonstrate the critical role played by the plasma-antenna-wave interaction around high-voltage space antennae and open the possibility to transmit high power in space. The physical insight obtained in this study can provide guidance to future high-power space-borne VLF transmitter developments, laboratory whistler-mode wave injection experiments, and the interpretation of various astrophysical and optical phenomena.
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5
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Drozdov AY, Allison HJ, Shprits YY, Usanova M, Saikin A, Wang D. Depletions of Multi-MeV Electrons and Their Association to Minima in Phase Space Density. Geophys Res Lett 2022; 49:e2021GL097620. [PMID: 35866059 PMCID: PMC9286695 DOI: 10.1029/2021gl097620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/15/2022] [Accepted: 04/03/2022] [Indexed: 06/15/2023]
Abstract
Fast-localized electron loss, resulting from interactions with electromagnetic ion cyclotron (EMIC) waves, can produce deepening minima in phase space density (PSD) radial profiles. Here, we perform a statistical analysis of local PSD minima to quantify how readily these are associated with radiation belt depletions. The statistics of PSD minima observed over a year are compared to the Versatile Electron Radiation Belts (VERB) simulations, both including and excluding EMIC waves. The observed minima distribution can only be achieved in the simulation including EMIC waves, indicating their importance in the dynamics of the radiation belts. By analyzing electron flux depletions in conjunction with the observed PSD minima, we show that, in the heart of the outer radiation belt (L* < 5), on average, 53% of multi-MeV electron depletions are associated with PSD minima, demonstrating that fast localized loss by interactions with EMIC waves are a common and crucial process for ultra-relativistic electron populations.
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Affiliation(s)
- A. Y. Drozdov
- University of California Los AngelesLos AngelesCAUSA
| | | | - Y. Y. Shprits
- University of California Los AngelesLos AngelesCAUSA
- GFZ German Centre for GeosciencesPotsdamGermany
- Institute of Physics and AstronomyUniversity of PotsdamPotsdamGermany
| | - M.E. Usanova
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - A. Saikin
- University of California Los AngelesLos AngelesCAUSA
| | - D. Wang
- GFZ German Centre for GeosciencesPotsdamGermany
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6
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Woodfield EE, Glauert SA, Menietti JD, Horne RB, Kavanagh AJ, Shprits YY. Acceleration of Electrons by Whistler-Mode Hiss Waves at Saturn. Geophys Res Lett 2022; 49:e2021GL096213. [PMID: 35864852 PMCID: PMC9286411 DOI: 10.1029/2021gl096213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/01/2021] [Accepted: 12/27/2021] [Indexed: 06/15/2023]
Abstract
Plasmaspheric hiss waves at the Earth are well known for causing losses of electrons from the radiation belts through wave particle interactions. At Saturn, however, we show that the different plasma density environment leads to acceleration of the electrons rather than loss. The ratio of plasma frequency to electron gyrofrequency frequently falls below one creating conditions for hiss to accelerate electrons. The location of hiss at high latitudes (>25°) coincides very well with this region of very low density. The interaction between electrons and hiss only occurs at these higher latitudes, therefore the acceleration is limited to mid to low pitch angles leading to butterfly pitch angle distributions. The hiss is typically an order of magnitude stronger than chorus at Saturn and the resulting acceleration is rapid, approaching steady state in one day at 0.4 MeV at L = 7 and the effect is stronger with increasing L-shell.
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7
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Staples FA, Kellerman A, Murphy KR, Rae IJ, Sandhu JK, Forsyth C. Resolving Magnetopause Shadowing Using Multimission Measurements of Phase Space Density. J Geophys Res Space Phys 2022; 127:e2021JA029298. [PMID: 35864842 PMCID: PMC9286781 DOI: 10.1029/2021ja029298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 12/21/2021] [Accepted: 01/10/2022] [Indexed: 06/15/2023]
Abstract
Loss mechanisms act independently or in unison to drive rapid loss of electrons in the radiation belts. Electrons may be lost by precipitation into the Earth's atmosphere, or through the magnetopause into interplanetary space-a process known as magnetopause shadowing. While magnetopause shadowing is known to produce dropouts in electron flux, it is unclear if shadowing continues to remove particles in tandem with electron acceleration processes, limiting the overall flux increase. We investigated the contribution of shadowing to overall radiation belt fluxes throughout a geomagnetic storm starting on the 7 September 2017. We use new, multimission phase space density calculations to decipher electron dynamics during each storm phase and identify features of magnetopause shadowing during both the net-loss and the net-acceleration storm phases on sub-hour time scales. We also highlight two distinct types of shadowing; "direct," where electrons are lost as their orbit intersects the magnetopause, and "indirect," where electrons are lost through ULF wave driven radial transport toward the magnetopause boundary.
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Affiliation(s)
- F. A. Staples
- Mullard Space Science LaboratoryUniversity College LondonLondonUK
| | - A. Kellerman
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | | | - I. J. Rae
- Northumbria UniversityNewcastle upon TyneUK
| | | | - C. Forsyth
- Mullard Space Science LaboratoryUniversity College LondonLondonUK
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8
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Miyoshi Y, Hosokawa K, Kurita S, Oyama SI, Ogawa Y, Saito S, Shinohara I, Kero A, Turunen E, Verronen PT, Kasahara S, Yokota S, Mitani T, Takashima T, Higashio N, Kasahara Y, Matsuda S, Tsuchiya F, Kumamoto A, Matsuoka A, Hori T, Keika K, Shoji M, Teramoto M, Imajo S, Jun C, Nakamura S. Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae. Sci Rep 2021; 11:13724. [PMID: 34257336 PMCID: PMC8277844 DOI: 10.1038/s41598-021-92611-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/14/2021] [Indexed: 11/16/2022] Open
Abstract
Pulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.
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Affiliation(s)
- Y Miyoshi
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan.
| | - K Hosokawa
- Graduate School of Communication Engineering and Informatics, University of Electro-Communications, Chofu, 182-8585, Japan
| | - S Kurita
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, 611-0011, Japan
| | - S-I Oyama
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan.,National Institute of Polar Research, Tachikawa, 190-8518, Japan.,University of Oulu, Pentti Kaiteran katu 1, Linnanmaa, Oulu, Finland
| | - Y Ogawa
- National Institute of Polar Research, Tachikawa, 190-8518, Japan.,The Graduate University for Advanced Studies, SOKENDAI, Hayama, 240-0193, Japan.,Joint Support-Center for Data Science Research, Research Organization of Information and Systems, Tachikawa, 190-8518, Japan
| | - S Saito
- National Institute of Information and Communications Technology, Tokyo, 184-8795, Japan
| | - I Shinohara
- Japan Aerospace Exploration Agency (JAXA), Sagamihara, 252-5210, Japan
| | - A Kero
- Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
| | - E Turunen
- Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
| | - P T Verronen
- Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland.,Space and Earth Observation Centre, Finnish Meteorological Institute, Helsinki, Finland
| | - S Kasahara
- Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - S Yokota
- Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - T Mitani
- Japan Aerospace Exploration Agency (JAXA), Sagamihara, 252-5210, Japan
| | - T Takashima
- Japan Aerospace Exploration Agency (JAXA), Sagamihara, 252-5210, Japan
| | - N Higashio
- Japan Aerospace Exploration Agency (JAXA), Sagamihara, 252-5210, Japan
| | - Y Kasahara
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - S Matsuda
- Japan Aerospace Exploration Agency (JAXA), Sagamihara, 252-5210, Japan
| | - F Tsuchiya
- Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - A Kumamoto
- Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - A Matsuoka
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - T Hori
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan
| | - K Keika
- Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - M Shoji
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan
| | - M Teramoto
- Graduate School of Engineering, Kyushu Institute of Technology, Fukuoka, 820-8501, Japan
| | - S Imajo
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - C Jun
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan
| | - S Nakamura
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601, Japan
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9
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Foster JC, Erickson PJ, Omura Y. Subpacket structure in strong VLF chorus rising tones: characteristics and consequences for relativistic electron acceleration. Earth Planets Space 2021; 73:140. [PMID: 34720649 PMCID: PMC8550140 DOI: 10.1186/s40623-021-01467-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Van Allen Probes in situ observations are used to examine detailed subpacket structure observed in strong VLF (very low frequency) rising-tone chorus elements observed at the time of a rapid MeV electron energization in the inner magnetosphere. Analysis of the frequency gap between lower and upper chorus-band waves identifies f ceEQ, the electron gyrofrequency in the equatorial wave generation region. Initial subpackets in these strong chorus rising-tone elements begin at a frequency near 1/4 f ceEQ and exhibit smooth gradual frequency increase across their > 10 ms temporal duration. A second much stronger subpacket is seen at frequencies around the local value of 1/4 f ce with small wave normal angle (< 10°) and steeply rising df/dt. Smooth frequency and phase variation across and between the initial subpackets support continuous phase trapping of resonant electrons and increased potential for MeV electron acceleration. The total energy gain for individual seed electrons with energies between 100 keV and 3 MeV ranges between 2 and 15%, in their nonlinear interaction with a single chorus element.
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Affiliation(s)
| | | | - Yoshiharu Omura
- Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan
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10
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Palma F, Sotgiu A, Parmentier A, Martucci M, Piersanti M, Bartocci S, Battiston R, Burger WJ, Campana D, Carfora L, Castellini G, Conti L, Contin A, D’angelo G, De Donato CD, De Santis CD, Follega FM, Iuppa R, Lazzizzera I, Marcelli N, Masciantonio G, Mergé M, Oliva A, Osteria G, Palmonari F, Panico B, Perfetto F, Picozza P, Pozzato M, Ricci E, Ricci M, Ricciarini SB, Sahnoun Z, Scotti V, Sparvoli R, Vitale V, Zoffoli S, Zuccon P. The August 2018 Geomagnetic Storm Observed by the High-Energy Particle Detector on Board the CSES-01 Satellite. Applied Sciences 2021; 11:5680. [DOI: 10.3390/app11125680] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
On 25 August 2018, a G3-class geomagnetic storm reached the Earth’s magnetosphere, causing a transient rearrangement of the charged particle environment around the planet, which was detected by the High-Energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01). We found that the count rates of electrons in the MeV range were characterized by a depletion during the storm’s main phase and a clear enhancement during the recovery caused by large substorm activity, with the key role played by auroral processes mapped into the outer belt. A post-storm rate increase was localized at L-shells immediately above ∼3 and mostly driven by non-adiabatic local acceleration caused by possible resonant interaction with low-frequency magnetospheric waves.
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11
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Abstract
Electrically charged particles are trapped by the Earth's magnetic field, forming the Van Allen radiation belts. Observations show that electrons in this region can have energies in excess of 7 MeV. However, whether electrons at these ultra-relativistic energies are locally accelerated, arise from betatron and Fermi acceleration due to transport across the magnetic field, or if a combination of both mechanisms is required, has remained an unanswered question in radiation belt physics. Here, we present a unique way of analyzing satellite observations which demonstrates that local acceleration is capable of heating electrons up to 7 MeV. By considering the evolution of phase space density peaks in magnetic coordinate space, we observe distinct signatures of local acceleration and the subsequent outward radial diffusion of ultra-relativistic electron populations. The results have important implications for understanding the origin of ultra-relativistic electrons in Earth's radiation belts, as well as in magnetized plasmas throughout the solar system.
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Affiliation(s)
- Hayley J Allison
- GFZ German Research Centre for Geosciences, 14473, Potsdam, Germany.
| | - Yuri Y Shprits
- GFZ German Research Centre for Geosciences, 14473, Potsdam, Germany
- Institute of Physics and Astronomy, Universität Potsdam, 14469, Potsdam, Germany
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, 90095, USA
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12
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Wang D, Shprits YY. On How High-Latitude Chorus Waves Tip the Balance Between Acceleration and Loss of Relativistic Electrons. Geophys Res Lett 2019; 46:7945-7954. [PMID: 31749506 PMCID: PMC6851667 DOI: 10.1029/2019gl082681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/03/2019] [Accepted: 06/29/2019] [Indexed: 06/10/2023]
Abstract
Modeling and observations have shown that energy diffusion by chorus waves is an important source of acceleration of electrons to relativistic energies. By performing long-term simulations using the three-dimensional Versatile Electron Radiation Belt code, in this study, we test how the latitudinal dependence of chorus waves can affect the dynamics of the radiation belt electrons. Results show that the variability of chorus waves at high latitudes is critical for modeling of megaelectron volt (MeV) electrons. We show that, depending on the latitudinal distribution of chorus waves under different geomagnetic conditions, they cannot only produce a net acceleration but also a net loss of MeV electrons. Decrease in high-latitude chorus waves can tip the balance between acceleration and loss toward acceleration, or alternatively, the increase in high-latitude waves can result in a net loss of MeV electrons. Variations in high-latitude chorus may account for some of the variability of MeV electrons.
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Affiliation(s)
- Dedong Wang
- Section 2.8 Magnetospheric PhysicsGFZ German Research Centre for GeosciencesPotsdamGermany
| | - Yuri Y. Shprits
- Section 2.8 Magnetospheric PhysicsGFZ German Research Centre for GeosciencesPotsdamGermany
- Institute of Physics and AstronomyUniversity of PotsdamPotsdamGermany
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
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13
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Daglis IA, Katsavrias C, Georgiou M. From solar sneezing to killer electrons: outer radiation belt response to solar eruptions. Philos Trans A Math Phys Eng Sci 2019; 377:20180097. [PMID: 31079586 PMCID: PMC6527955 DOI: 10.1098/rsta.2018.0097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Electrons in the outer Van Allen (radiation) belt occasionally reach relativistic energies, turning them into a potential hazard for spacecraft operating in geospace. Such electrons have secured the reputation of satellite killers and play a prominent role in space weather. The flux of these electrons can vary over time scales of years (related to the solar cycle) to minutes (related to sudden storm commencements). Electric fields and plasma waves are the main factors regulating the electron transport, acceleration and loss. Both the fields and the plasma waves are driven directly or indirectly by disturbances originating in the Sun, propagating through interplanetary space and impacting the Earth. This paper reviews our current understanding of the response of outer Van Allen belt electrons to solar eruptions and their interplanetary extensions, i.e. interplanetary coronal mass ejections and high-speed solar wind streams and the associated stream interaction regions. This article is part of the theme issue 'Solar eruptions and their space weather impact'.
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Affiliation(s)
- Ioannis A. Daglis
- Department of Physics, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute of Accelerating Systems and Applications, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, 15236 Penteli, Greece
| | - Christos Katsavrias
- Department of Physics, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute of Accelerating Systems and Applications, National and Kapodistrian University of Athens, 15487 Athens, Greece
| | - Marina Georgiou
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Dorking RH5 6NT, UK
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14
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Baker DN, Hoxie V, Zhao H, Jaynes AN, Kanekal S, Li X, Elkington S. Multiyear Measurements of Radiation Belt Electrons: Acceleration, Transport, and Loss. J Geophys Res Space Phys 2019; 124:2588-2602. [PMID: 31245234 PMCID: PMC6582599 DOI: 10.1029/2018ja026259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/21/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
In addition to clarifying morphological structures of the Earth's radiation belts, it has also been a major achievement of the Van Allen Probes mission to understand more thoroughly how highly relativistic and ultrarelativistic electrons are accelerated deep inside the radiation belts. Prior studies have demonstrated that electrons up to energies of 10 megaelectron volts (MeV) can be produced over broad regions of the outer Van Allen zone on timescales of minutes to a few hours. It often is seen that geomagnetic activity driven by strong solar storms (i.e., coronal mass ejections, or CMEs) almost inexorably leads to relativistic electron production through the intermediary step of intense magnetospheric substorms. In this study, we report observations over the 6-year period 1 September 2012 to 1 September 2018. We focus on data about the relativistic and ultrarelativistic electrons (E≥5 MeV) measured by the Relativistic Electron-Proton Telescope sensors on board the Van Allen Probes spacecraft. This work portrays the radiation belt acceleration, transport, and loss characteristics over a wide range of geomagnetic events. We emphasize features seen repeatedly in the data (three-belt structures, "impenetrable" barrier properties, and radial diffusion signatures) in the context of acceleration and loss mechanisms. We especially highlight solar wind forcing of the ultrarelativistic electron populations and extended periods when such electrons were absent. The analysis includes new display tools showing spatial features of the mission-long time variability of the outer Van Allen belt emphasizing the remarkable dynamics of the system.
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Affiliation(s)
- Daniel N. Baker
- Laboratory for Atmospheric and Space PhysicsUniversity of ColoradoBoulderCOUSA
| | - Vaughn Hoxie
- Laboratory for Atmospheric and Space PhysicsUniversity of ColoradoBoulderCOUSA
| | - Hong Zhao
- Laboratory for Atmospheric and Space PhysicsUniversity of ColoradoBoulderCOUSA
| | | | | | - Xinlin Li
- Laboratory for Atmospheric and Space PhysicsUniversity of ColoradoBoulderCOUSA
| | - Scot Elkington
- Laboratory for Atmospheric and Space PhysicsUniversity of ColoradoBoulderCOUSA
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15
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Aseev NA, Shprits YY, Wang D, Wygant J, Drozdov AY, Kellerman AC, Reeves GD. Transport and Loss of Ring Current Electrons Inside Geosynchronous Orbit During the 17 March 2013 Storm. J Geophys Res Space Phys 2019; 124:915-933. [PMID: 31008006 PMCID: PMC6472511 DOI: 10.1029/2018ja026031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/04/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
Ring current electrons (1-100 keV) have received significant attention in recent decades, but many questions regarding their major transport and loss mechanisms remain open. In this study, we use the four-dimensional Versatile Electron Radiation Belt code to model the enhancement of phase space density that occurred during the 17 March 2013 storm. Our model includes global convection, radial diffusion, and scattering into the Earth's atmosphere driven by whistler-mode hiss and chorus waves. We study the sensitivity of the model to the boundary conditions, global electric field, the electric field associated with subauroral polarization streams, electron loss rates, and radial diffusion coefficients. The results of the code are almost insensitive to the model parameters above 4.5 R E R E, which indicates that the general dynamics of the electrons between 4.5 R E and the geostationary orbit can be explained by global convection. We found that the major discrepancies between the model and data can stem from the inaccurate electric field model and uncertainties in lifetimes. We show that additional mechanisms that are responsible for radial transport are required to explain the dynamics of ≥40-keV electrons, and the inclusion of the radial diffusion rates that are typically assumed in radiation belt studies leads to a better agreement with the data. The overall effect of subauroral polarization streams on the electron phase space density profiles seems to be smaller than the uncertainties in other input parameters. This study is an initial step toward understanding the dynamics of these particles inside the geostationary orbit.
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Affiliation(s)
- N. A. Aseev
- GFZ German Research Centre for GeosciencesPotsdamGermany
- Institute of Physics and AstronomyUniversity of PotsdamPotsdamGermany
| | - Y. Y. Shprits
- GFZ German Research Centre for GeosciencesPotsdamGermany
- Institute of Physics and AstronomyUniversity of PotsdamPotsdamGermany
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | - D. Wang
- GFZ German Research Centre for GeosciencesPotsdamGermany
| | - J. Wygant
- School of Physics and AstronomyUniversity of MinnesotaMinneapolisMNUSA
| | - A. Y. Drozdov
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | - A. C. Kellerman
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
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16
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Kalmoni NME, Rae IJ, Watt CEJ, Murphy KR, Samara M, Michell RG, Grubbs G, Forsyth C. A diagnosis of the plasma waves responsible for the explosive energy release of substorm onset. Nat Commun 2018; 9:4806. [PMID: 30442968 PMCID: PMC6237928 DOI: 10.1038/s41467-018-07086-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/31/2018] [Indexed: 11/08/2022] Open
Abstract
During geomagnetic substorms, stored magnetic and plasma thermal energies are explosively converted into plasma kinetic energy. This rapid reconfiguration of Earth's nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere. Here, we exploit state-of-the-art auroral measurements to construct an observational dispersion relation of waves during substorm onset. Further, we use kinetic theory of high-beta plasma to demonstrate that the shear Alfven wave dispersion relation bears remarkable similarity to the auroral dispersion relation. In contrast to prevailing theories of substorm initiation, we demonstrate that auroral beads seen during the majority of substorm onsets are likely the signature of kinetic Alfven waves driven unstable in the high-beta magnetotail.
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Affiliation(s)
- N M E Kalmoni
- Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, RH5 6NT, UK.
| | - I J Rae
- Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, RH5 6NT, UK.
| | - C E J Watt
- Department of Meteorology, University of Reading, Reading, RG6 6BB, UK.
| | - K R Murphy
- Department of Astronomy, University of Maryland, College Park, 20742, MD, USA
| | - M Samara
- NASA Goddard Space Flight Center, Greenbelt, 20771, MD, USA
| | - R G Michell
- NASA Goddard Space Flight Center, Greenbelt, 20771, MD, USA
| | - G Grubbs
- NASA Goddard Space Flight Center, Greenbelt, 20771, MD, USA
| | - C Forsyth
- Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, RH5 6NT, UK
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17
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Jaynes AN, Ali AF, Elkington SR, Malaspina DM, Baker DN, Li X, Kanekal SG, Henderson MG, Kletzing CA, Wygant JR. Fast Diffusion of Ultrarelativistic Electrons in the Outer Radiation Belt: 17 March 2015 Storm Event. Geophys Res Lett 2018; 45:10874-10882. [PMID: 31007304 PMCID: PMC6472651 DOI: 10.1029/2018gl079786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 05/17/2023]
Abstract
Inward radial diffusion driven by ULF waves has long been known to be capable of accelerating radiation belt electrons to very high energies within the heart of the belts, but more recent work has shown that radial diffusion values can be highly event-specific, and mean values or empirical models may not capture the full significance of radial diffusion to acceleration events. Here we present an event of fast inward radial diffusion, occurring during a period following the geomagnetic storm of 17 March 2015. Ultrarelativistic electrons up to ∼8 MeV are accelerated in the absence of intense higher-frequency plasma waves, indicating an acceleration event in the core of the outer belt driven primarily or entirely by ULF wave-driven diffusion. We examine this fast diffusion rate along with derived radial diffusion coefficients using particle and fields instruments on the Van Allen Probes spacecraft mission.
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Affiliation(s)
- A. N. Jaynes
- Department of Physics & AstronomyUniversity of IowaIowa CityIAUSA
| | - A. F. Ali
- Air Force Research LabKirtland Air Force BaseAlbuquerqueNMUSA
- Laboratory for Atmospheric and Space ScienceUniversity of Colorado BoulderBoulderCOUSA
| | - S. R. Elkington
- Laboratory for Atmospheric and Space ScienceUniversity of Colorado BoulderBoulderCOUSA
| | - D. M. Malaspina
- Laboratory for Atmospheric and Space ScienceUniversity of Colorado BoulderBoulderCOUSA
| | - D. N. Baker
- Laboratory for Atmospheric and Space ScienceUniversity of Colorado BoulderBoulderCOUSA
| | - X. Li
- Laboratory for Atmospheric and Space ScienceUniversity of Colorado BoulderBoulderCOUSA
| | - S. G. Kanekal
- Division of HeliophysicsNASA Goddard Space Flight CenterGreenbeltMDUSA
| | | | - C. A. Kletzing
- Department of Physics & AstronomyUniversity of IowaIowa CityIAUSA
| | - J. R. Wygant
- Department of PhysicsUniversity of Minnesota, Twin CitiesMinneapolisMNUSA
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18
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Kitamura N, Kitahara M, Shoji M, Miyoshi Y, Hasegawa H, Nakamura S, Katoh Y, Saito Y, Yokota S, Gershman DJ, Vinas AF, Giles BL, Moore TE, Paterson WR, Pollock CJ, Russell CT, Strangeway RJ, Fuselier SA, Burch JL. Direct measurements of two-way wave-particle energy transfer in a collisionless space plasma. Science 2018; 361:1000-1003. [PMID: 30190400 DOI: 10.1126/science.aap8730] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 07/04/2018] [Indexed: 11/02/2022]
Abstract
Particle acceleration by plasma waves and spontaneous wave generation are fundamental energy and momentum exchange processes in collisionless plasmas. Such wave-particle interactions occur ubiquitously in space. We present ultrafast measurements in Earth's magnetosphere by the Magnetospheric Multiscale spacecraft that enabled quantitative evaluation of energy transfer in interactions associated with electromagnetic ion cyclotron waves. The observed ion distributions are not symmetric around the magnetic field direction but are in phase with the plasma wave fields. The wave-ion phase relations demonstrate that a cyclotron resonance transferred energy from hot protons to waves, which in turn nonresonantly accelerated cold He+ to energies up to ~2 kilo-electron volts. These observations provide direct quantitative evidence for collisionless energy transfer in plasmas between distinct particle populations via wave-particle interactions.
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Affiliation(s)
- N Kitamura
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan. .,Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - M Kitahara
- Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan
| | - M Shoji
- Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan
| | - Y Miyoshi
- Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan
| | - H Hasegawa
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
| | - S Nakamura
- Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Japan
| | - Y Katoh
- Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Y Saito
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
| | - S Yokota
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - A F Vinas
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,Department of Physics, American University, Washington, DC, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - T E Moore
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | - C T Russell
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA
| | - R J Strangeway
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA
| | - S A Fuselier
- Southwest Research Institute, San Antonio, TX, USA.,University of Texas at San Antonio, San Antonio, TX, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, TX, USA
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19
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Horne RB, Phillips MW, Glauert SA, Meredith NP, Hands ADP, Ryden KA, Li W. Realistic Worst Case for a Severe Space Weather Event Driven by a Fast Solar Wind Stream. Space Weather 2018; 16:1202-1215. [PMID: 31031572 PMCID: PMC6473668 DOI: 10.1029/2018sw001948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/19/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
Satellite charging is one of the most important risks for satellites on orbit. Satellite charging can lead to an electrostatic discharge resulting in component damage, phantom commands, and loss of service and in exceptional cases total satellite loss. Here we construct a realistic worst case for a fast solar wind stream event lasting 5 days or more and use a physical model to calculate the maximum electron flux greater than 2 MeV for geostationary orbit. We find that the flux tends toward a value of 106 cm-2·s-1·sr-1 after 5 days and remains high for another 5 days. The resulting flux is comparable to a 1 in 150-year event found from an independent statistical analysis of electron data. Approximately 2.5 mm of Al shielding would be required to reduce the internal charging current to below the National Aeronautics and Space Administration-recommended guidelines, much more than is currently used. Thus, we would expect many satellites to report electrostatic discharge anomalies during such an event with a strong likelihood of service outage and total satellite loss. We conclude that satellites at geostationary orbit are more likely to be at risk from fast solar wind stream event than a Carrington-type storm.
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Affiliation(s)
| | | | | | | | | | | | - Wen Li
- Center for Space PhysicsBoston UniversityBostonMAUSA
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20
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Antonova EE, Stepanova MV, Moya PS, Pinto VA, Vovchenko VV, Ovchinnikov IL, Sotnikov NV. Processes in auroral oval and outer electron radiation belt. Earth Planets Space 2018; 70:127. [PMID: 30956530 PMCID: PMC6428230 DOI: 10.1186/s40623-018-0898-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
We have analyzed the role of auroral processes in the formation of the outer radiation belt, considering that the main part of the auroral oval maps to the outer part of the ring current, instead of the plasma sheet as is commonly postulated. In this approach, the outer ring current is the region where transverse magnetospheric currents close inside the magnetosphere. Specifically, we analyzed the role of magnetospheric substorms in the appearance of relativistic electrons in the outer radiation belt. We present experimental evidence that the presence of substorms during a geomagnetic storm recovery phase is, in fact, very important for the appearance of a new radiation belt during this phase. We discuss the possible role of adiabatic acceleration of relativistic electrons during storm recovery phase and show that this mechanism may accelerate the relativistic electrons by more than one order of magnitude.
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Affiliation(s)
- Elizaveta E. Antonova
- Skobeltsyn Institute of Nuclear Physics and Space Research Institute RAS, Lomonosov Moscow State University, Moscow, Russia
| | - Marina V. Stepanova
- Departamento de Fisica, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - Pablo S. Moya
- Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Victor A. Pinto
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, USA
| | | | - Ilya L. Ovchinnikov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Nikita V. Sotnikov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
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21
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Shprits YY, Menietti JD, Drozdov AY, Horne RB, Woodfield EE, Groene JB, de Soria-Santacruz M, Averkamp TF, Garrett H, Paranicas C, Gurnett DA. Strong whistler mode waves observed in the vicinity of Jupiter's moons. Nat Commun 2018; 9:3131. [PMID: 30087326 DOI: 10.1038/s41467-018-05431-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 06/28/2018] [Indexed: 11/09/2022] Open
Abstract
Understanding of wave environments is critical for the understanding of how particles are accelerated and lost in space. This study shows that in the vicinity of Europa and Ganymede, that respectively have induced and internal magnetic fields, chorus wave power is significantly increased. The observed enhancements are persistent and exceed median values of wave activity by up to 6 orders of magnitude for Ganymede. Produced waves may have a pronounced effect on the acceleration and loss of particles in the Jovian magnetosphere and other astrophysical objects. The generated waves are capable of significantly modifying the energetic particle environment, accelerating particles to very high energies, or producing depletions in phase space density. Observations of Jupiter’s magnetosphere provide a unique opportunity to observe how objects with an internal magnetic field can interact with particles trapped in magnetic fields of larger scale objects. Observations of Jupiter’s magnetosphere provide opportunities to understand how magnetic fields interact with particles. Here, the authors report that the chorus wave power is increased in the vicinity of Europa and Ganymede. The generated waves are able to accelerate particles to very high energy.
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22
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Ozeke LG, Mann IR, Murphy KR, Degeling AW, Claudepierre SG, Spence HE. Explaining the apparent impenetrable barrier to ultra-relativistic electrons in the outer Van Allen belt. Nat Commun 2018; 9:1844. [PMID: 29748536 DOI: 10.1038/s41467-018-04162-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 04/11/2018] [Indexed: 11/29/2022] Open
Abstract
Recent observations have shown the existence of an apparent impenetrable barrier at the inner edge of the ultra-relativistic outer electron radiation belt. This apparent impenetrable barrier has not been explained. However, recent studies have suggested that fast loss, such as associated with scattering into the atmosphere from man-made very-low frequency transmissions, is required to limit the Earthward extent of the belt. Here we show that the steep flux gradient at the implied barrier location is instead explained as a natural consequence of ultra-low frequency wave radial diffusion. Contrary to earlier claims, sharp boundaries in fast loss processes at the barrier are not needed. Moreover, we show that penetration to the barrier can occur on the timescale of days rather than years as previously reported, with the Earthward extent of the belt being limited by the finite duration of strong solar wind driving, which can encompass only a single geomagnetic storm. The origin of the apparent impenetrable barrier in the outer Van Allen belt is still uncertain. Here, the authors report that penetration to the barrier can occur by means of ultra-low frequency wave transport, enabling ultra-relativistic electrons to reach the location of the barrier.
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23
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Kilpua E, Koskinen HEJ, Pulkkinen TI. Coronal mass ejections and their sheath regions in interplanetary space. Living Rev Sol Phys 2017; 14:5. [PMID: 31997985 PMCID: PMC6956910 DOI: 10.1007/s41116-017-0009-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 10/03/2017] [Indexed: 06/09/2023]
Abstract
Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.
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Affiliation(s)
- Emilia Kilpua
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Hannu E. J. Koskinen
- Department of Physics, University of Helsinki, Helsinki, Finland
- Finnish Meteorological Institute, Espoo, Finland
| | - Tuija I. Pulkkinen
- Department of Electronics and Nanoengineering, Aalto University, Espoo, Finland
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24
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Anderson DC, Nicely JM, Wolfe GM, Hanisco TF, Salawitch RJ, Canty TP, Dickerson RR, Apel EC, Baidar S, Bannan TJ, Blake NJ, Chen D, Dix B, Fernandez RP, Hall SR, Hornbrook RS, Huey LG, Josse B, Jöckel P, Kinnison DE, Koenig TK, LeBreton M, Marécal V, Morgenstern O, Oman LD, Pan LL, Percival C, Plummer D, Revell LE, Rozanov E, Saiz-Lopez A, Stenke A, Sudo K, Tilmes S, Ullmann K, Volkamer R, Weinheimer AJ, Zeng G. Formaldehyde in the Tropical Western Pacific: Chemical sources and sinks, convective transport, and representation in CAM-Chem and the CCMI models. J Geophys Res Atmos 2017. [PMID: 29527424 DOI: 10.1002/2017ja024474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Formaldehyde (HCHO) directly affects the atmospheric oxidative capacity through its effects on HOx. In remote marine environments, such as the Tropical Western Pacific (TWP), it is particularly important to understand the processes controlling the abundance of HCHO because model output from these regions is used to correct satellite retrievals of HCHO. Here, we have used observations from the CONTRAST field campaign, conducted during January and February 2014, to evaluate our understanding of the processes controlling the distribution of HCHO in the TWP as well as its representation in chemical transport/climate models. Observed HCHO mixing ratios varied from ~500 pptv near the surface to ~75 pptv in the upper troposphere. Recent convective transport of near surface HCHO and its precursors, acetaldehyde and possibly methyl hydroperoxide, increased upper tropospheric HCHO mixing ratios by ~33% (22 pptv); this air contained roughly 60% less NO than more aged air. Output from the CAM-Chem chemistry transport model (2014 meteorology) as well as nine chemistry climate models from the Chemistry-Climate Model Initiative (free-running meteorology) are found to uniformly underestimate HCHO columns derived from in situ observations by between 4 and 50%. This underestimate of HCHO likely results from a near factor of two underestimate of NO in most models, which strongly suggests errors in NOx emissions inventories and/or in the model chemical mechanisms. Likewise, the lack of oceanic acetaldehyde emissions and potential errors in the model acetaldehyde chemistry lead to additional underestimates in modeled HCHO of up to 75 pptv (~15%) in the lower troposphere.
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Affiliation(s)
- Daniel C Anderson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA
| | - Julie M Nicely
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Universities Space Research Association, Columbia, Maryland, USA
| | - Glenn M Wolfe
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Thomas F Hanisco
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Ross J Salawitch
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA
| | - Timothy P Canty
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA
| | - Russell R Dickerson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA
| | - Eric C Apel
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Sunil Baidar
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, USA
| | | | - Nicola J Blake
- Department of Chemistry, University of California, Irvine, California, USA
| | - Dexian Chen
- School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Barbara Dix
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
| | - Rafael P Fernandez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
- Department of Natural Science, National Research Council (CONICET), FCEN-UNCuyo, Mendoza, Argentina
| | - Samuel R Hall
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | | | - L Gregory Huey
- School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Beatrice Josse
- Centre National de Recherche Météorologique, UMR3589, Méteo-France-CNRS, Toulouse, France
| | - Patrick Jöckel
- Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
| | | | - Theodore K Koenig
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, USA
| | - Michael LeBreton
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Virginie Marécal
- Centre National de Recherche Météorologique, UMR3589, Méteo-France-CNRS, Toulouse, France
| | - Olaf Morgenstern
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Luke D Oman
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Laura L Pan
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Carl Percival
- Department of Chemistry, University of Manchester, UK
| | - David Plummer
- Canadian Centre for Climate Modeling and Analysis, Environment Canada, Victoria, British Columbia, Canada
| | - Laura E Revell
- Bodeker Scientific, Alexandra, New Zealand
- ETH Zürich, Institute for Atmospheric and Climate Science, Zürich, Switzerland
| | - Eugene Rozanov
- ETH Zürich, Institute for Atmospheric and Climate Science, Zürich, Switzerland
- Physikalisch-Meteorologisches Observatorium Davos World Radiation Centre, Davos Dorf, Switzerland
| | - Alfonso Saiz-Lopez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
| | - Andrea Stenke
- ETH Zürich, Institute for Atmospheric and Climate Science, Zürich, Switzerland
| | - Kengo Sudo
- Nagoya University, Graduate School of Environmental Studies, Nagoya, Japan
- Japan Marine-Earth Science and Technology, Yokohama, Japan
| | - Simone Tilmes
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Kirk Ullmann
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Rainer Volkamer
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, USA
| | | | - Guang Zeng
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
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25
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Hidding B, Karger O, Königstein T, Pretzler G, Manahan GG, McKenna P, Gray R, Wilson R, Wiggins SM, Welsh GH, Beaton A, Delinikolas P, Jaroszynski DA, Rosenzweig JB, Karmakar A, Ferlet-Cavrois V, Costantino A, Muschitiello M, Daly E. Laser-plasma-based Space Radiation Reproduction in the Laboratory. Sci Rep 2017; 7:42354. [PMID: 28176862 PMCID: PMC5296722 DOI: 10.1038/srep42354] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/08/2017] [Indexed: 11/23/2022] Open
Abstract
Space radiation is a great danger to electronics and astronauts onboard space vessels. The spectral flux of space electrons, protons and ions for example in the radiation belts is inherently broadband, but this is a feature hard to mimic with conventional radiation sources. Using laser-plasma-accelerators, we reproduced relativistic, broadband radiation belt flux in the laboratory, and used this man-made space radiation to test the radiation hardness of space electronics. Such close mimicking of space radiation in the lab builds on the inherent ability of laser-plasma-accelerators to directly produce broadband Maxwellian-type particle flux, akin to conditions in space. In combination with the established sources, utilisation of the growing number of ever more potent laser-plasma-accelerator facilities worldwide as complementary space radiation sources can help alleviate the shortage of available beamtime and may allow for development of advanced test procedures, paving the way towards higher reliability of space missions.
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Affiliation(s)
- B Hidding
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - O Karger
- Institut für Experimentalphysik, University of Hamburg, Germany
| | - T Königstein
- Institute for Laser and Plasma Physics, Heinrich-Heine-University Düsseldorf, Germany
| | - G Pretzler
- Institute for Laser and Plasma Physics, Heinrich-Heine-University Düsseldorf, Germany
| | - G G Manahan
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - P McKenna
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - R Gray
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - R Wilson
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - S M Wiggins
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - G H Welsh
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - A Beaton
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - P Delinikolas
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | - D A Jaroszynski
- SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
| | | | - A Karmakar
- Leibniz Supercomputing Centre, Boltzmannstr. 1, 85748 Garching, Germany
| | | | | | | | - E Daly
- European Space Agency, Noordwijk, Netherlands
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26
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Shprits YY, Drozdov AY, Spasojevic M, Kellerman AC, Usanova ME, Engebretson MJ, Agapitov OV, Zhelavskaya IS, Raita TJ, Spence HE, Baker DN, Zhu H, Aseev NA. Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts. Nat Commun 2016; 7:12883. [PMID: 27678050 DOI: 10.1038/ncomms12883] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 08/10/2016] [Indexed: 11/08/2022] Open
Abstract
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.
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27
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Jordanova VK, Tu W, Chen Y, Morley SK, Panaitescu A, Reeves GD, Kletzing CA. RAM-SCB simulations of electron transport and plasma wave scattering during the October 2012 "double-dip" storm. J Geophys Res Space Phys 2016; 121:8712-8727. [PMID: 27867801 PMCID: PMC5101868 DOI: 10.1002/2016ja022470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 08/31/2016] [Accepted: 09/03/2016] [Indexed: 06/06/2023]
Abstract
Mechanisms for electron injection, trapping, and loss in the near-Earth space environment are investigated during the October 2012 "double-dip" storm using our ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB). Pitch angle and energy scattering are included for the first time in RAM-SCB using L and magnetic local time (MLT)-dependent event-specific chorus wave models inferred from NOAA Polar-orbiting Operational Environmental Satellites (POES) and Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science observations. The dynamics of the source (approximately tens of keV) and seed (approximately hundreds of keV) populations of the radiation belts simulated with RAM-SCB is compared with Van Allen Probes Magnetic Electron Ion Spectrometer observations in the morning sector and with measurements from NOAA 15 satellite in the predawn and afternoon MLT sectors. We find that although the low-energy (E< 100 keV) electron fluxes are in good agreement with observations, increasing significantly by magnetospheric convection during both SYM-H dips while decreasing during the intermediate recovery phase, the injection of high-energy electrons is underestimated by this mechanism throughout the storm. Local acceleration by chorus waves intensifies the electron fluxes at E≥50 keV considerably, and RAM-SCB simulations overestimate the observed trapped fluxes by more than an order of magnitude; the precipitating fluxes simulated with RAM-SCB are weaker, and their temporal and spatial evolutions agree well with POES/Medium Energy Proton and Electron Detectors data.
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Affiliation(s)
- V. K. Jordanova
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - W. Tu
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
- Department of Physics and AstronomyWest Virginia UniversityMorgantownWest VirginiaUSA
| | - Y. Chen
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - S. K. Morley
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - A.‐D. Panaitescu
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - G. D. Reeves
- Space Science and ApplicationsLos Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - C. A. Kletzing
- Department of Physics and AstronomyUniversity of IowaIowa CityIowaUSA
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28
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Baker DN, Jaynes AN, Kanekal SG, Foster JC, Erickson PJ, Fennell JF, Blake JB, Zhao H, Li X, Elkington SR, Henderson MG, Reeves GD, Spence HE, Kletzing CA, Wygant JR. Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015. J Geophys Res Space Phys 2016; 121:6647-6660. [PMID: 27867796 PMCID: PMC5101849 DOI: 10.1002/2016ja022502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/02/2016] [Accepted: 06/27/2016] [Indexed: 05/28/2023]
Abstract
Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm (Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong "butterfly" distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported "impenetrable barrier" at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.
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Affiliation(s)
- D. N. Baker
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderColoradoUSA
| | - A. N. Jaynes
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderColoradoUSA
| | | | - J. C. Foster
- MIT Haystack ObservatoryWestfordMassachusettsUSA
| | | | | | - J. B. Blake
- The Aerospace CorporationLos AngelesCaliforniaUSA
| | - H. Zhao
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderColoradoUSA
| | - X. Li
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderColoradoUSA
| | - S. R. Elkington
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderColoradoUSA
| | | | - G. D. Reeves
- Los Alamos National LaboratoryLos AlamosNew MexicoUSA
| | - H. E. Spence
- Institute for the Study of Earth, Oceans, and SpaceUniversity of New HampshireDurhamNew HampshireUSA
| | - C. A. Kletzing
- Department of Physics and AstronomyUniversity of IowaIowa CityIowaUSA
| | - J. R. Wygant
- Department of Physics and AstronomyUniversity of Minnesota, Twin CitiesMinneapolisMinnesotaUSA
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29
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Forsyth C, Rae IJ, Murphy KR, Freeman MP, Huang C, Spence HE, Boyd AJ, Coxon JC, Jackman CM, Kalmoni NME, Watt CEJ. What effect do substorms have on the content of the radiation belts? J Geophys Res Space Phys 2016; 121:6292-6306. [PMID: 27656336 PMCID: PMC5014235 DOI: 10.1002/2016ja022620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 06/01/2023]
Abstract
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to 3 times as many increases in TRBEC following substorm intervals. There is a lag of 1-3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM-H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.
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Affiliation(s)
- C. Forsyth
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - I. J. Rae
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - K. R. Murphy
- NASA Goddard Space Flight CenterGreenbeltMarylandUSA
| | | | - C.‐L. Huang
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
| | - H. E. Spence
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
| | - A. J. Boyd
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
- New Mexico ConsortiumLos AlamosNew MexicoUSA
| | - J. C. Coxon
- School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - C. M. Jackman
- School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - N. M. E. Kalmoni
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - C. E. J. Watt
- Department of MeteorologyUniversity of ReadingReadingUK
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30
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Reeves GD, Friedel RHW, Larsen BA, Skoug RM, Funsten HO, Claudepierre SG, Fennell JF, Turner DL, Denton MH, Spence HE, Blake JB, Baker DN. Energy-dependent dynamics of keV to MeV electrons in the inner zone, outer zone, and slot regions. J Geophys Res Space Phys 2016; 121:397-412. [PMID: 27818855 PMCID: PMC5070526 DOI: 10.1002/2015ja021569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 06/01/2023]
Abstract
We present observations of the radiation belts from the Helium Oxygen Proton Electron and Magnetic Electron Ion Spectrometer particle detectors on the Van Allen Probes satellites that illustrate the energy dependence and L shell dependence of radiation belt enhancements and decays. We survey events in 2013 and analyze an event on 1 March in more detail. The observations show the following: (a) at all L shells, lower energy electrons are enhanced more often than higher energies; (b) events that fill the slot region are more common at lower energies; (c) enhancements of electrons in the inner zone are more common at lower energies; and (d) even when events do not fully fill the slot region, enhancements at lower energies tend to extend to lower L shells than higher energies. During enhancement events the outer zone extends to lower L shells at lower energies while being confined to higher L shells at higher energies. The inner zone shows the opposite with an outer boundary at higher L shells for lower energies. Both boundaries are nearly straight in log(energy) versus L shell space. At energies below a few 100 keV, radiation belt electron penetration through the slot region into the inner zone is commonplace, but the number and frequency of "slot filling" events decreases with increasing energy. The inner zone is enhanced only at energies that penetrate through the slot. Energy- and L shell-dependent losses (that are consistent with whistler hiss interactions) return the belts to more quiescent conditions.
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Affiliation(s)
- Geoffrey D Reeves
- Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA
| | - Reiner H W Friedel
- Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA
| | - Brian A Larsen
- Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA
| | - Ruth M Skoug
- Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA
| | - Herbert O Funsten
- Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA
| | | | | | - Drew L Turner
- The Aerospace Corporation Los Angeles California USA
| | | | - Harlan E Spence
- Institute for the Study of Earth, Oceans, and Space and Department of Physics University of New Hampshire Durham New Hampshire USA
| | | | - Daniel N Baker
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
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31
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Claudepierre SG, Toffoletto FR, Wiltberger M. Global MHD modeling of resonant ULF waves: Simulations with and without a plasmasphere. J Geophys Res Space Phys 2016; 121:227-244. [PMID: 27668142 PMCID: PMC5020600 DOI: 10.1002/2015ja022048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 11/20/2015] [Accepted: 12/07/2015] [Indexed: 06/06/2023]
Abstract
We investigate the plasmaspheric influence on the resonant mode coupling of magnetospheric ultralow frequency (ULF) waves using the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic (MHD) model. We present results from two different versions of the model, both driven by the same solar wind conditions: one version that contains a plasmasphere (the LFM coupled to the Rice Convection Model, where the Gallagher plasmasphere model is also included) and another that does not (the stand-alone LFM). We find that the inclusion of a cold, dense plasmasphere has a significant impact on the nature of the simulated ULF waves. For example, the inclusion of a plasmasphere leads to a deeper (more earthward) penetration of the compressional (azimuthal) electric field fluctuations, due to a shift in the location of the wave turning points. Consequently, the locations where the compressional electric field oscillations resonantly couple their energy into local toroidal mode field line resonances also shift earthward. We also find, in both simulations, that higher-frequency compressional (azimuthal) electric field oscillations penetrate deeper than lower frequency oscillations. In addition, the compressional wave mode structure in the simulations is consistent with a radial standing wave oscillation pattern, characteristic of a resonant waveguide. The incorporation of a plasmasphere into the LFM global MHD model represents an advance in the state of the art in regard to ULF wave modeling with such simulations. We offer a brief discussion of the implications for radiation belt modeling techniques that use the electric and magnetic field outputs from global MHD simulations to drive particle dynamics.
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Affiliation(s)
| | | | - M. Wiltberger
- High Altitude ObservatoryNational Center for Atmospheric ResearchBoulderColoradoUSA
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32
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Su Z, Zhu H, Xiao F, Zong QG, Zhou XZ, Zheng H, Wang Y, Wang S, Hao YX, Gao Z, He Z, Baker DN, Spence HE, Reeves GD, Blake JB, Wygant JR. Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons. Nat Commun 2015; 6:10096. [PMID: 26690250 PMCID: PMC4703845 DOI: 10.1038/ncomms10096] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/03/2015] [Indexed: 11/15/2022] Open
Abstract
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.
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Affiliation(s)
- Zhenpeng Su
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hui Zhu
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fuliang Xiao
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha Hunan 410004, China
| | - Q.-G. Zong
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - X.-Z. Zhou
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - Huinan Zheng
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuming Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shui Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Y.-X. Hao
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - Zhonglei Gao
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhaoguo He
- Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - D. N. Baker
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80303-7814, USA
| | - H. E. Spence
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824-3525, USA
| | - G. D. Reeves
- Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - J. B. Blake
- The Aerospace Corporation, Los Angeles, California 90245-4609, USA
| | - J. R. Wygant
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
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33
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Hartley DP, Chen Y, Kletzing CA, Denton MH, Kurth WS. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes. J Geophys Res Space Phys 2015; 120:1144-1152. [PMID: 26167444 PMCID: PMC4497456 DOI: 10.1002/2014ja020808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/20/2015] [Indexed: 05/17/2023]
Abstract
Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1-0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10-3 nT2, using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.
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Affiliation(s)
- D P Hartley
- Physics Department, Lancaster UniversityLancaster, UK
| | - Y Chen
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
| | - C A Kletzing
- Department of Physics and Astronomy, University of IowaIowa City, Iowa, USA
| | - M H Denton
- Space Science InstituteBoulder, Colorado, USA
| | - W S Kurth
- Department of Physics and Astronomy, University of IowaIowa City, Iowa, USA
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34
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Fu X, Cowee MM, Friedel RH, Funsten HO, Gary SP, Hospodarsky GB, Kletzing C, Kurth W, Larsen BA, Liu K, MacDonald EA, Min K, Reeves GD, Skoug RM, Winske D. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations. J Geophys Res Space Phys 2014; 119:8288-8298. [PMID: 26167433 PMCID: PMC4497467 DOI: 10.1002/2014ja020364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/27/2014] [Indexed: 05/17/2023]
Abstract
Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr <Ω e , where Ω e is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃Ω e /2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ∼Ω e /2 is a natural consequence of the growth of two whistler modes with different properties.
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Affiliation(s)
- Xiangrong Fu
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
| | - Misa M Cowee
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
| | | | | | | | | | - Craig Kletzing
- Department of Physics and Astronomy, University of IowaIowa City, Iowa, USA
| | - William Kurth
- Department of Physics and Astronomy, University of IowaIowa City, Iowa, USA
| | - Brian A Larsen
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
| | - Kaijun Liu
- Department of Physics, Auburn UniversityAuburn, Alabama, USA
| | | | - Kyungguk Min
- Department of Physics, Auburn UniversityAuburn, Alabama, USA
| | | | - Ruth M Skoug
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
| | - Dan Winske
- Los Alamos National LaboratoryLos Alamos, New Mexico, USA
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35
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Pakhotin IP, Drozdov AY, Shprits YY, Boynton RJ, Subbotin DA, Balikhin MA. Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes. J Geophys Res Space Phys 2014; 119:8073-8086. [PMID: 26167432 PMCID: PMC4497480 DOI: 10.1002/2014ja020238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/09/2014] [Indexed: 06/04/2023]
Abstract
This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes for various magnetospheric conditions. Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed.
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Affiliation(s)
- I P Pakhotin
- Department of Automatic Control and Systems Engineering, University of SheffieldSheffield, UK
| | - A Y Drozdov
- Department of Earth and Space Sciences, University of CaliforniaLos Angeles, California, USA
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State UniversityMoscow, Russia
| | - Y Y Shprits
- Department of Earth and Space Sciences, University of CaliforniaLos Angeles, California, USA
- Department of Atmospheric and Planetary Sciences, Massachusetts Institute of TechnologyCambridge, Massachusetts, USA
- Skolkovo Institute of Science and TechnologySkolkovo, Russia
| | - R J Boynton
- Department of Automatic Control and Systems Engineering, University of SheffieldSheffield, UK
| | - D A Subbotin
- Department of Earth and Space Sciences, University of CaliforniaLos Angeles, California, USA
| | - M A Balikhin
- Department of Automatic Control and Systems Engineering, University of SheffieldSheffield, UK
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36
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Mozer FS, Agapitov O, Krasnoselskikh V, Lejosne S, Reeves GD, Roth I. Direct observation of radiation-belt electron acceleration from electron-volt energies to megavolts by nonlinear whistlers. Phys Rev Lett 2014; 113:035001. [PMID: 25083648 DOI: 10.1103/physrevlett.113.035001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Indexed: 06/03/2023]
Abstract
The mechanisms for accelerating electrons from thermal to relativistic energies in the terrestrial magnetosphere, on the sun, and in many astrophysical environments have never been verified. We present the first direct observation of two processes that, in a chain, cause this acceleration in Earth's outer radiation belt. The two processes are parallel acceleration from electron-volt to kilovolt energies by parallel electric fields in time-domain structures (TDS), after which the parallel electron velocity becomes sufficiently large for Doppler-shifted upper band whistler frequencies to be in resonance with the electron gyration frequency, even though the electron energies are kilovolts and not hundreds of kilovolts. The electrons are then accelerated by the whistler perpendicular electric field to relativistic energies in several resonant interactions. TDS are packets of electric field spikes, each spike having duration of a few hundred microseconds and containing a local parallel electric field. The TDS of interest resulted from nonlinearity of the parallel electric field component in oblique whistlers and consisted of ∼ 0.1 msec pulses superposed on the whistler waveform with each such spike containing a net parallel potential the order of 50 V. Local magnetic field compression from remote activity provided the free energy to drive the two processes. The expected temporal correlations between the compressed magnetic field, the nonlinear whistlers with their parallel electric field spikes, the electron flux and the electron pitch angle distributions were all observed.
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Affiliation(s)
- F S Mozer
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - O Agapitov
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA and Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
| | - V Krasnoselskikh
- Laboratoire de Physique et de Chimie de l'Environnement et de l'Espace (LPC2E), CNRS, Orleans 45171, France
| | - S Lejosne
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - G D Reeves
- Space and Atmospheric Sciences Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - I Roth
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
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37
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Van Compernolle B, Bortnik J, Pribyl P, Gekelman W, Nakamoto M, Tao X, Thorne RM. Direct detection of resonant electron pitch angle scattering by whistler waves in a laboratory plasma. Phys Rev Lett 2014; 112:145006. [PMID: 24765981 DOI: 10.1103/physrevlett.112.145006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 06/03/2023]
Abstract
Resonant interactions between energetic electrons and whistler mode waves are an essential ingredient in the space environment, and in particular in controlling the dynamic variability of Earth's natural radiation belts, which is a topic of extreme interest at the moment. Although the theory describing resonant wave-particle interaction has been present for several decades, it has not been hitherto tested in a controlled laboratory setting. In the present Letter we report on the first laboratory experiment to directly detect resonant pitch angle scattering of energetic (∼keV) electrons due to whistler mode waves. We show that the whistler mode wave deflects energetic electrons at precisely the predicted resonant energy, and that varying both the maximum beam energy, and the wave frequency, alters the energetic electron beam very close to the resonant energy.
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Affiliation(s)
- B Van Compernolle
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - J Bortnik
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - P Pribyl
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - W Gekelman
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - M Nakamoto
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - X Tao
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - R M Thorne
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
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Thorne RM, Li W, Ni B, Ma Q, Bortnik J, Chen L, Baker DN, Spence HE, Reeves GD, Henderson MG, Kletzing CA, Kurth WS, Hospodarsky GB, Blake JB, Fennell JF, Claudepierre SG, Kanekal SG. Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus. Nature 2013; 504:411-4. [PMID: 24352287 DOI: 10.1038/nature12889] [Citation(s) in RCA: 517] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/18/2013] [Indexed: 11/09/2022]
Abstract
Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt, but are inconsistent with acceleration by inward radial diffusive transport. However, the precise physical mechanism responsible for the acceleration on 9 October was not identified. Previous modelling has indicated that a magnetospheric electromagnetic emission known as chorus could be a potential candidate for local electron acceleration, but a definitive resolution of the importance of chorus for radiation-belt acceleration was not possible because of limitations in the energy range and resolution of previous electron observations and the lack of a dynamic global wave model. Here we report high-resolution electron observations obtained during the 9 October storm and demonstrate, using a two-dimensional simulation performed with a recently developed time-varying data-driven model, that chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase. Our detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt, and the results presented have potential application to Jupiter, Saturn and other magnetized astrophysical objects.
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39
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Affiliation(s)
- Mary K Hudson
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755-3528, USA
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40
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Mozer FS, Bale SD, Bonnell JW, Chaston CC, Roth I, Wygant J. Megavolt parallel potentials arising from double-layer streams in the Earth's outer radiation belt. Phys Rev Lett 2013; 111:235002. [PMID: 24476280 DOI: 10.1103/physrevlett.111.235002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Indexed: 05/28/2023]
Abstract
Huge numbers of double layers carrying electric fields parallel to the local magnetic field line have been observed on the Van Allen probes in connection with in situ relativistic electron acceleration in the Earth's outer radiation belt. For one case with adequate high time resolution data, 7000 double layers were observed in an interval of 1 min to produce a 230,000 V net parallel potential drop crossing the spacecraft. Lower resolution data show that this event lasted for 6 min and that more than 1,000,000 volts of net parallel potential crossed the spacecraft during this time. A double layer traverses the length of a magnetic field line in about 15 s and the orbital motion of the spacecraft perpendicular to the magnetic field was about 700 km during this 6 min interval. Thus, the instantaneous parallel potential along a single magnetic field line was the order of tens of kilovolts. Electrons on the field line might experience many such potential steps in their lifetimes to accelerate them to energies where they serve as the seed population for relativistic acceleration by coherent, large amplitude whistler mode waves. Because the double-layer speed of 3100 km/s is the order of the electron acoustic speed (and not the ion acoustic speed) of a 25 eV plasma, the double layers may result from a new electron acoustic mode. Acceleration mechanisms involving double layers may also be important in planetary radiation belts such as Jupiter, Saturn, Uranus, and Neptune, in the solar corona during flares, and in astrophysical objects.
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Affiliation(s)
- F S Mozer
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - S D Bale
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - J W Bonnell
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - C C Chaston
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - I Roth
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - J Wygant
- Physics Department, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Mann IR, Lee EA, Claudepierre SG, Fennell JF, Degeling A, Rae IJ, Baker DN, Reeves GD, Spence HE, Ozeke LG, Rankin R, Milling DK, Kale A, Friedel RHW, Honary F. Discovery of the action of a geophysical synchrotron in the Earth’s Van Allen radiation belts. Nat Commun 2013. [DOI: 10.1038/ncomms3795] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Cowen R. Mystery of Earth's radiation belts solved. Nature 2013. [DOI: 10.1038/nature.2013.13452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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