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Turc L, Roberts OW, Verscharen D, Dimmock AP, Kajdič P, Palmroth M, Pfau-Kempf Y, Johlander A, Dubart M, Kilpua EKJ, Soucek J, Takahashi K, Takahashi N, Battarbee M, Ganse U. Transmission of foreshock waves through Earth's bow shock. Nat Phys 2022; 19:78-86. [PMID: 36687291 PMCID: PMC9845118 DOI: 10.1038/s41567-022-01837-z] [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: 02/25/2021] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
The Earth's magnetosphere and its bow shock, which is formed by the interaction of the supersonic solar wind with the terrestrial magnetic field, constitute a rich natural laboratory enabling in situ investigations of universal plasma processes. Under suitable interplanetary magnetic field conditions, a foreshock with intense wave activity forms upstream of the bow shock. So-called 30 s waves, named after their typical period at Earth, are the dominant wave mode in the foreshock and play an important role in modulating the shape of the shock front and affect particle reflection at the shock. These waves are also observed inside the magnetosphere and down to the Earth's surface, but how they are transmitted through the bow shock remains unknown. By combining state-of-the-art global numerical simulations and spacecraft observations, we demonstrate that the interaction of foreshock waves with the shock generates earthward-propagating, fast-mode waves, which reach the magnetosphere. These findings give crucial insight into the interaction of waves with collisionless shocks in general and their impact on the downstream medium.
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Affiliation(s)
- L. Turc
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - O. W. Roberts
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - D. Verscharen
- Mullard Space Science Laboratory, University College London, Dorking, UK
| | | | - P. Kajdič
- Departamento de Ciencias Espaciales, Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - M. Palmroth
- Department of Physics, University of Helsinki, Helsinki, Finland
- Finnish Meteorological Institute, Helsinki, Finland
| | - Y. Pfau-Kempf
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - A. Johlander
- Department of Physics, University of Helsinki, Helsinki, Finland
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - M. Dubart
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - E. K. J. Kilpua
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - J. Soucek
- Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - K. Takahashi
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - N. Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Tokyo, Japan
- Radio Research Institute, National Institute of Information and Communication Technology, Tokyo, Japan
| | - M. Battarbee
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - U. Ganse
- Department of Physics, University of Helsinki, Helsinki, Finland
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