Intense Vibrations of the Martian Ionosphere Observed by MARSIS Active Sounding during a Sun--Earth--Mars Conjunction

Abstract:

The ISSI Working Group on The Induced Magnetosphere of Mars: Physical Processes and Consquences has covered three conjunction campaigns, in which the Sun, Earth,and Mars are lined up radially. During these campaigns data taken on the Sun, at Earth, and from spacecraft in solar orbit such as STEREO can be applied to events occurring in the Martian ionosphere to gauge the response to events in the solar wind more precisely than at other times when solar wind data cannot be accurately projected to Mars. In this presentation, we apply data from all of these sources as well as the Mars Express spacecraft in order to characterize a few events in which MARSIS Active Ionospheric Sounding, the topside sounder on board the Mars Express spacecraft, detects intense vibrations of period about 10 s in both locally detected electron density and magnetic field strength and remotely sensed electron density profiles near the ionospheric peak. That these vibrations appear both locally and in the remote sensing indicates the global nature of this phenomenon. The vibrations are seen to occur as the effect of one or more ICME impacts on the Martian ionosphere.