Do We Need to Consider Electrons' Kinetic Effects to Properly Model a Planetary Magnetosphere: The Case of Mercury

0557094 - ÚFA 2023 RIV US eng J - Journal Article
Lapenta, G. - Schriver, D. - Walker, R. J. - Berchem, J. - Echterling, N.F. - El Alaoui, M. - Trávníček, Pavel
Do We Need to Consider Electrons' Kinetic Effects to Properly Model a Planetary Magnetosphere: The Case of Mercury.
Journal of Geophysical Research-Space Physics. Roč. 127, č. 4 (2022), č. článku e2021JA030241. ISSN 2169-9380. E-ISSN 2169-9402
Institutional support: RVO:68378289
Keywords : messenger observations * magnetic-field * spatial-distribution * solar-wind * reconnection * simulations * magnetopause * plasma * energy * multiscale
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 2.8, year: 2022
Method of publishing: Open access
https://lirias.kuleuven.be/bitstream/20.500.12942/695439/2/Lapenta_data.docx

The magnetosphere of Mercury is studied using an implicit full particle-in-cell simulation (PIC). We use a hybrid simulation where ions are full particles and electrons are considered as a fluid to start a PIC simulation where electrons are also particles and follow their distribution function. This approach allows us to estimate the changes introduced by the electron kinetic physics. We find that the overall macroscopic state of the magnetosphere of Mercury is little affected, but several physical processes are significantly modified in the full PIC simulation: the foreshock region is more active with more intense shock reformation, the Kelvin-Helmholtz rippling effects on the nightside magnetopause are sharper, and the magnetotail current sheet becomes thinner than those predicted by the hybrid simulation. The greatest effect of the electron physics comes from the processes of particle energization. Both species, not just the electrons, are found to gain more energy when kinetic electron processes are included. The region with the most energetic plasma is found on the dusk side of the tail where magnetic flux ropes are formed due to reconnection. We find that the ion and electron energization is associated with the regions of reconnection and the development of kinetic instabilities caused by counter-streaming electron populations. The resulting electron distributions are highly non Maxwellian, a process that neither MHD nor hybrid models can describe.
Permanent Link: http://hdl.handle.net/11104/0331317