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A survey of superthermal electron flux depressions, or “electron holes,” within the illuminated Martian induced magnetosphere

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journal contribution
posted on 02.06.2016, 12:30 by Benjamin E. S. Hall, Mark Lester, Jonathan D. Nichols, Beatriz sanchez-cano, D. J. Andrews, H. J. Opgenoorth, M. Franz
Since Mars lacks a global intrinsic magnetic field, the solar wind interacts directly with the Martian upper atmosphere and ionosphere. The presence of localized intense remnant crustal magnetic fields adds to this interaction, making the Martian plasma system a unique environment within the solar system. Rapid reductions in the electron flux, referred to as “electron holes,” occur within the Martian induced magnetosphere (IM). We present a statistical analysis of this phenomenon identified from proxy measurements of the electron flux derived from measurements by the Analyser of Space Plasmas and Energetic Neutral Atoms Electron Spectrometer experiment on board the Mars Express (MEX) spacecraft. The study is completed for the period of 9 February 2004 to 9 May 2014. Electron holes are observed within the IM in more than 56% of MEX orbits during this study period, occurring predominantly at altitudes less than 1300 km, with the majority in the negative X Mars-Centric Solar Orbital direction. The spatial distribution above the surface of Mars is observed to bear close resemblance to that of the crustal magnetic fields as predicted by the Cain et al. [2003] magnetic field model, suggesting that they play an important role in the formation of these phenomena.

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Citation

Journal of Geophysical Research: Space Physics, 2016, 121 (5), pp. 4835-4857

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Journal of Geophysical Research: Space Physics

Publisher

Wiley for American Geophysical Union (AGU)

issn

2169-9402

Acceptance date

09/05/2016

Copyright date

2016

Available date

02/06/2016

Publisher version

http://onlinelibrary.wiley.com/doi/10.1002/2015JA021866/abstract

Language

en

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