The coronal mass ejection interaction with the induced magnetosphere of Mars due to the 27 January 2012 solar storm

An X-class flare on 27 January 2012 generated a high-energy particle stream advancing along the interplanetary magnetic field (IMF) which arrived at Mars in about 39 minutes, with a coronal mass ejection (CME) released from the same active region arriving at Mars several days later. The Electron Spectrometer (ELS), part of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment on the European Mars Express (MEx) Spacecraft, is used to show that the effect of the CME plasma caused an increase in the intensity of the electron distribution function within the Martian magnetosheath. Models of this event predicted the speed, morphology, and Martian impact of the CME. The Mars reaction, being an induced magnetosphere, responds to changes in solar wind conditions by continually self adjusting its magnetosheath to stand off the solar wind. Since the ion component of the solar wind interaction carries momentum away from the Sun, it is the electrons with their significantly greater mobility that must self adjust in order to maintain charge neutrality and the proper induced current flow in order to stand-off changes in the solar wind.