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Kollmann P, Hill ME, Allen RC, McNutt RL, Brown LE, Barnes NP, Delamere P, Clark G, Andrews GB, Salazar N, Westlake J, Romeo G, Vandegriff J, Kusterer M, Smith D, Nelson K, Jaskulek S, Decker RB, Cheng AF, Krimigis SM, Lisse CM, Mitchell DG, Weaver HA, Elliott HA, Fattig E, Gladstone GR, Valek PW, Weidner S, Kammer J, Bagenal F, Horanyi M, Kaufmann D, Harch A, Olkin CB, Piquette MR, Spencer JR, Young LA, Ennico K, Summers ME, Stern SA. Pluto's Interaction With Energetic Heliospheric Ions. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2019; 124:7413-7424. [PMID: 35860291 PMCID: PMC9285724 DOI: 10.1029/2019ja026830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 06/15/2023]
Abstract
Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto. The intensity is increasing exponentially with distance to Pluto and reaches nominal levels of the interplanetary medium at about 190R P distance. Inside the wake of Pluto, we observe oscillations of the ion intensities with a periodicity of about 0.2 hr. We show that these can be quantitatively explained by the electric field of an ultralow-frequency wave and discuss possible physical drivers for such a field. We find no evidence for the presence of plutogenic ions in the considered energy range.
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Bagenal F, Horányi M, McComas DJ, McNutt RL, Elliott HA, Hill ME, Brown LE, Delamere PA, Kollmann P, Krimigis SM, Kusterer M, Lisse CM, Mitchell DG, Piquette M, Poppe AR, Strobel DF, Szalay JR, Valek P, Vandegriff J, Weidner S, Zirnstein EJ, Stern SA, Ennico K, Olkin CB, Weaver HA, Young LA. Pluto's interaction with its space environment: Solar wind, energetic particles, and dust. Science 2016; 351:aad9045. [PMID: 26989259 DOI: 10.1126/science.aad9045] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The New Horizons spacecraft carried three instruments that measured the space environment near Pluto as it flew by on 14 July 2015. The Solar Wind Around Pluto (SWAP) instrument revealed an interaction region confined sunward of Pluto to within about 6 Pluto radii. The region's surprisingly small size is consistent with a reduced atmospheric escape rate, as well as a particularly high solar wind flux. Observations from the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument suggest that ions are accelerated and/or deflected around Pluto. In the wake of the interaction region, PEPSSI observed suprathermal particle fluxes equal to about 1/10 of the flux in the interplanetary medium and increasing with distance downstream. The Venetia Burney Student Dust Counter, which measures grains with radii larger than 1.4 micrometers, detected one candidate impact in ±5 days around New Horizons' closest approach, indicating an upper limit of <4.6 kilometers(-3) for the dust density in the Pluto system.
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Affiliation(s)
- F Bagenal
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80600, USA.
| | - M Horányi
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80600, USA
| | - D J McComas
- Southwest Research Institute, San Antonio, TX 78228, USA. University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - R L McNutt
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - H A Elliott
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - M E Hill
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - L E Brown
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | - P Kollmann
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - S M Krimigis
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
| | - M Kusterer
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - C M Lisse
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - D G Mitchell
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - M Piquette
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80600, USA
| | - A R Poppe
- Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA
| | - D F Strobel
- Johns Hopkins University, Baltimore, MD 21218, USA
| | - J R Szalay
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80600, USA. Southwest Research Institute, Boulder, CO 80302, USA
| | - P Valek
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - J Vandegriff
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - S Weidner
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - E J Zirnstein
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - S A Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - K Ennico
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - C B Olkin
- Southwest Research Institute, Boulder, CO 80302, USA
| | - H A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - L A Young
- Southwest Research Institute, Boulder, CO 80302, USA
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