Inferring Whistler‐Mode Chorus Wave Source Regions in the Martian Mini‐Magnetospheres

Abstract

Abstract Martian mini‐magnetospheres contain whistler‐mode chorus waves potentially contributing to atmospheric escape, analogous to the Earth's inner magnetosphere. At Earth, the chorus waves have been found to originate from the near‐equatorial region spanning approximately 2% of the entire magnetic field line length. However, because of the lack of wave Poynting flux measurements, the Martian chorus source region remains unclear. By comparing the frequency dependence between observed wave power and modeled linear growth rates, we present the first attempt to explore the chorus wave source distribution along the Martian mini‐magnetospheric field lines. Our data‐to‐model comparisons support that these waves are not generated by a single source tightly confined near the magnetic strength minimal location but by intermittent or continuous sources spanning up to 40% of the entire field line length. These results imply that the Martian mini‐magnetospheres could have more active energy transfer processes mediated by whistler‐mode chorus waves than the expectation.