Low-frequency electromagnetic waves and instabilities within the Martian bi-ion plasma

摘要: The Martian environment is characterized by the presence of heavy (oxygen) ions planetary origin which strongly influence solar wind dynamics, including bow shock structure and position may cause additional plasma boundaries in magnetosheath. In this paper dispersion characteristics low-frequency electromagnetic waves (LFEW) proton gyrofrequency range are studied. excitation these results from relative motion between protons ions, considered as unmagnetized and, therefore, act like a beam wind. model takes into account small extension magnetosphere compared with pickup gyroradius an exospheric ion. From analysis it was found that most unstable relatively high growth rates propagate oblique to ambient magnetic field. For propagation angle field right-hand polarized whistler frame, due Doppler shift they appear near cyclotron frequency left-hand (spacecraft) frame. We suggest sporadic LFEW emission seen upstream region Mars Phobos-2 indicate existence localized “heavy ion bunches” whose unclear, but possible relation moons cannot be excluded. Especially, so-called Phobos events marked spectral peaks around interpreted signatures interaction tenuous gas torus. A comparable situation known AMPTE Ba Li releases where during late stages experiments enhanced observed well. Another important aspect its role deceleration heating turbulent processes provide strong momentum coupling newly generated origin.