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Sodium Ion Dynamics in the Magnetospheric Flanks of Mercury
Author(s) -
Aizawa Sae,
Delcourt Dominique,
Terada Naoki
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076586
Subject(s) - physics , magnetosheath , magnetopause , geophysics , solar wind , instability , exosphere , planet , magnetohydrodynamics , space physics , ion , magnetic field , computational physics , mechanics , astrophysics , quantum mechanics
We investigate the transport of planetary ions in the magnetospheric flanks of Mercury. In situ measurements from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft show evidences of Kelvin‐Helmholtz instability development in this region of space, due to the velocity shear between the downtail streaming flow of solar wind originating protons in the magnetosheath and the magnetospheric populations. Ions that originate from the planet exosphere and that gain access to this region of space may be transported across the magnetopause along meandering orbits. We examine this transport using single‐particle trajectory calculations in model Magnetohydrodynamics simulations of the Kelvin‐Helmholtz instability. We show that heavy ions of planetary origin such as Na + may experience prominent nonadiabatic energization as they E × B drift across large‐scale rolled up vortices. This energization is controlled by the characteristics of the electric field burst encountered along the particle path, the net energy change realized corresponding to the maximum E × B drift energy. This nonadiabatic energization also is responsible for prominent scattering of the particles toward the direction perpendicular to the magnetic field.