Analysis of multiscale structures at the quasi-perpendicular Venus bow shock Results from Solar Orbiter's first Venus flyby

0557220 - ASÚ 2023 RIV FR eng J - Článek v odborném periodiku
Dimmock, A. - Khotyaintsev, Y. - Lalti, A. - Štverák, Štěpán - Trávníček, Pavel M. … celkem 26 autorů
Analysis of multiscale structures at the quasi-perpendicular Venus bow shock Results from Solar Orbiter's first Venus flyby.
Astronomy & Astrophysics. Roč. 660, April (2022), č. článku A64. ISSN 0004-6361. E-ISSN 1432-0746
Institucionální podpora: RVO:67985815
Klíčová slova: waves observed upstream * whistler-mode waves * high mach number
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 6.5, rok: 2022
Způsob publikování: Open access

This study aims to investigate the outbound Venus bow shock crossing measured by Solar Orbiter during the first flyby. We study the complex features of the bow shock traversal in which multiple large amplitude magnetic field and density structures were observed as well as higher frequency waves. Our aim is to understand the physical mechanisms responsible for these high amplitude structures, characterize the higher frequency waves, determine the source of the waves, and put these results into context with terrestrial bow shock observations. Methods. High cadence magnetic field, electric field, and electron density measurements were employed to characterize the properties of the large amplitude structures and identify the relevant physical process. Minimum variance analysis, theoretical shock descriptions, coherency analysis, and singular value decomposition were used to study the properties of the higher frequency waves to compare and identify the wave mode. The non-planar features of the bow shock are consistent with shock rippling and/or large amplitude whistler waves. Higher frequency waves are identified as whistler-mode waves, but their properties across the shock imply they may be generated by electron beams and temperature anisotropies. Conclusions. The Venus bow shock at a moderately high Mach number (similar to 5) in the quasi-perpendicular regime exhibits complex features similar to the Earth's bow shock at comparable Mach numbers. The study highlights the need to be able to distinguish between large amplitude waves and spatial structures such as shock rippling. The simultaneous high frequency observations also demonstrate the complex nature of energy dissipation at the shock and the important question of understanding cross-scale coupling in these complex regions. These observations will be important to interpreting future planetary missions and additional gravity assist maneuvers.
Trvalý link: http://hdl.handle.net/11104/0331633