Journal article
MAVEN Observations of Solar Wind‐Driven Magnetosonic Waves Heating the Martian Dayside Ionosphere
Journal of geophysical research. Space physics, Vol.123(5), pp.4129-4149
05/2018
DOI: 10.1029/2018JA025208
Abstract
We present Mars Atmosphere and Volatile EvolutioN observations of large‐amplitude magnetosonic waves propagating through the magnetosheath into the Martian ionosphere near the subsolar point on the dayside of the planet. The observed waves grow in amplitude as predicted for a wave propagating into a denser, charged medium, with wave amplitudes reaching 25 nT, equivalent to ∼40% of the background field strength. These waves drive significant density and temperature variations (∼20% to 100% in amplitude) in the suprathermal electrons and light ion species (H+) that correlate with compressional fronts of the magnetosonic waves. Density and temperature variations are also observed for the ionospheric electrons, and heavy ion species (O+ and O
2+); however, these variations are not in phase with the magnetic field variations. Whistler waves are observed at compressional wave fronts and are thought to be produced by unstable, anistropic suprathermal electrons. The magnetosonic waves drive significant ion and electron heating down to just above the exobase region. Ion heating rates are estimated to be between 0.03 and 0.2 eVs−1 per ion, and heavier ions could thus gain escape energy if located in this heating region for ∼10–70 s. The measured ionospheric density profile indicates severe ionospheric erosion above the exobase region, and this is likely caused by substantial ion outflow that is driven by the observed heating. The effectiveness of these magnetosonic waves to energize the plasma close to the exobase could have important implications for the long‐term climate evolution for unmagnetized bodies that are exposed to the solar wind.
Key Points
Magnetosonic waves are observed to propagate from the magnetosheath into the dayside Martian ionosphere
Magnetosonic waves are observed to drive large variations in ionospheric density and temperature
Wave energy is absorbed by the dense O
2+ ionosphere, leading to significant ion heating and substantial ionospheric erosion
Details
- Title: Subtitle
- MAVEN Observations of Solar Wind‐Driven Magnetosonic Waves Heating the Martian Dayside Ionosphere
- Creators
- C. M Fowler - University of Colorado BoulderL Andersson - University of Colorado BoulderR. E Ergun - University of Colorado BoulderY Harada - University of IowaT Hara - University of California, BerkeleyG Collinson - Goddard Space Flight CenterW. K Peterson - University of Colorado BoulderJ Espley - Goddard Space Flight CenterJ Halekas - University of IowaJ Mcfadden - University of California, BerkeleyD. L Mitchell - University of California, BerkeleyC Mazelle - Université de ToulouseM Benna - Goddard Space Flight CenterB. M Jakosky - University of Colorado Boulder
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.123(5), pp.4129-4149
- DOI
- 10.1029/2018JA025208
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 21
- Grant note
- NASA (NNH10CC04C)
- Language
- English
- Date published
- 05/2018
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199698702771
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