Journal article
Seasonal variability of Martian ion escape through the plume and tail from MAVEN observations
Journal of geophysical research. Space physics, Vol.122(4), pp.4009-4022
04/2017
DOI: 10.1002/2016JA023517
Abstract
We study the Mars Atmosphere and Volatile Evolution spacecraft observations of Martian planetary ion escape during two time periods: 11 November 2014 to 19 March 2015 and 4 June 2015 to 24 October 2015, with the focus on understanding the seasonal variability of Martian ion escape in response to the solar extreme ultraviolet (EUV) flux. We organize the >6 eV O+ ion data by the upstream electric field direction to estimate the escape rates through the plume and tail. To investigate the ion escape dependence on the solar EUV flux, we constrain the solar wind dynamic pressure and interplanetary magnetic filed strength and compare the ion escape rates through the plume and tail in different energy ranges under high and low EUV conditions. We found that the total >6 eV O+ escape rate increases from 2 to 3 × 1024 s−1 as the EUV irradiance increases by almost the same factor, mostly on the <1 keV tailward escape. The plume escape rate does not vary significantly with EUV. The relative contribution from the plume to the total escape varies between ~30% and ~20% from low to high EUV. Our results suggest that the Martian ion escape is sensitive to the seasonal EUV variation, and the contribution from plume escape becomes more important under low EUV conditions.
Key Points
The total >6 eV O+ ion escape rate increases from 2 to 3 × 1024 s−1 as the EUV irradiance increases by almost the same factor
The tailward escape rate increases with EUV, while the plume escape rate does not change significantly
The ratio of the plume escape to the total escape drops from ~30% to ~20% as the EUV increases
Details
- Title: Subtitle
- Seasonal variability of Martian ion escape through the plume and tail from MAVEN observations
- Creators
- Y Dong - University of Colorado BoulderX Fang - University of Colorado BoulderD. A Brain - University of Colorado BoulderJ. P McFadden - University of California, BerkeleyJ. S Halekas - University of IowaJ. E. P Connerney - Goddard Space Flight CenterF Eparvier - University of Colorado BoulderL Andersson - University of Colorado BoulderD Mitchell - University of California, BerkeleyB. M Jakosky - University of Colorado Boulder
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.122(4), pp.4009-4022
- DOI
- 10.1002/2016JA023517
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 14
- Grant note
- NASA MAVEN Mars Exploration Program
- Language
- English
- Date published
- 04/2017
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199803602771
Metrics
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