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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - A survey of superthermal electron flux depressions, or “electron holes” within the illuminated Martian induced magnetosphere
AU - Hall, Benjamin Edward Stanley
AU - Lester, Mark
AU - Nichols, Jonathan
AU - Sánchez-Cano, Beatriz
AU - Andrews, David
AU - Opgenoorth, Hermann
AU - Fraenz, Markus
PY - 2016/5/13
Y1 - 2016/5/13
N2 - 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.
AB - 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.
KW - Mars
KW - Crustal Magnetic Fields
KW - Electron Holes
KW - Ionospheres
KW - solar wind planetary interactions
KW - unmagnetised bodies
KW - Mars Express
U2 - 10.1002/2015JA021866
DO - 10.1002/2015JA021866
M3 - Journal article
VL - 121
SP - 4835
EP - 4857
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9380
IS - 5
ER -