Magnetic Pumping in Planetary Magnetospheres: Comparisons at Mars and Earth

Magnetic pumping allows the transfer of energy from magnetosonic waves (low frequency, compressive) at magnetohydrodynamical (MHD) scales, to electrons at kinetic scales in space plasmas. This can lead to significant localized heating of ambient electrons in planetary magnetospheres, and has been seen at induced (Mars, Venus) and intrinsic (Earth) magnetospheres. At Mars, the smaller scale size of the induced magnetosphere means that the underlying low frequency waves that drive the pumping can propagate into the planetary ionospheres, where the process can heat ionospheric electrons. The process can thus couple the solar wind to the ionosphere, where it can drive processes such as atmospheric loss to space via enhanced ambipolar electric fields.  

At Mars, pumping events have been identified using MAVEN data, which can resolve the MHD scales of this process. At Earth, MMS can resolve the kinetic scale physics, allowing more detailed analysis into magnetic pumping. Comparisons between the two planets allow conclusions to be drawn about the similarities and differences between this process at induced vs intrinsic magnetospheres. We present detailed case studies of magnetic pumping at both Mars and Earth.