Journal article
Ionospheric Plasma Transported Into the Martian Magnetosheath
Geophysical research letters, Vol.51(6), e2023GL107953
03/28/2024
DOI: 10.1029/2023GL107953
Abstract
Heavy cold ions at Mars are gravitationally bound to the planet unless some process provides energy to them. Observations show that cold (<20 eV) and dense (∼>1 cm−3) O+/O2+ ions with bulk velocities equal to energies ∼1 keV can reach deep into the nightside Martian magnetosheath. These ions are co‐located with a change of the sign of the sunward component of the magnetic field. This magnetic field topology implies the persistence of a localized planetary ions escape channel associated with draped magnetic field lines that are convecting tailward. The observed ion populations propagate approximately in the same direction as surrounding magnetosheath flow and are likely to be almost unheated ionospheric ions from low altitudes. The paper discusses planetary ion energization via Hall electric field originated from ions and electron separation associated with magnetic field curvature.
Plain Language Summary
In‐situ observations above the nightside of Mars show the presence of localized dense planetary ion fluxes at altitudes exceeding 2,000 km and escaping from the planet at high energies, comparable to that of the solar wind. These fluxes are accompanied by the reversal of sunward component of magnetic field. Unlike most atmospheric escape channels, the reported phenomenon is characterized by an increase in heavy to light ions density ratio with the distance from the planet at the observed altitudes up to nearly 5,000 km, as well as an increase in overall plasma number density inside this escape channel relative to the ambient sheath environment. This behavior is consistent with acceleration process initiated by a bent magnetic flux tube.
Key Points
Ions of different species gain similar energies in the Martian magnetosheath by Hall electric fields associated with magnetic curvature
A high concentration of ionospheric ions correlates with a near void of shocked solar wind protons and a magnetic field reversal
Number density at the reversal increases with distance from Mars in comparison to the surrounding sheath at least till two Martian radii
Details
- Title: Subtitle
- Ionospheric Plasma Transported Into the Martian Magnetosheath
- Creators
- Sergey Shuvalov - University of Colorado BoulderLaila Andersson - University of Colorado BoulderJasper S. Halekas - University of IowaChristopher M. Fowler - West Virginia UniversityKathleen Gwen Hanley - University of California, BerkeleyGina DiBraccio - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.51(6), e2023GL107953
- DOI
- 10.1029/2023GL107953
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 10
- Grant note
- National Aeronautics and Space Administration (NNH10CC04 C)
- Language
- English
- Date published
- 03/28/2024
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984577036202771
Metrics
1 Record Views