The Properities Of Whistler Waves In The Earth's Space Plasmas

The whistler waves are widely existed in the solar wind,interplanetary shocks and the Earth's space plasmas,which waves play an important role in electron acceleration and deposition in the radiation belt,energetic electron acceleration in the solar wind,and rapid magnetic reconnection.Although a lot of work has been carried out on the whistler waves'characteristics,the theories of the whistler waves are not complete.Furthermore,the existing theories are not enough to analyze and explain the observed whistler waves.In this paper,the dispersion relationship and electromagnetic response characteristics of magnetosonic-whistler wave mode?M/W mode?are fully investigated using the kinetic and fluid theories.The results of this study under the kinetic and fluid theories are compared in detail,and the M/W wave mode and low-frequency waves properties of multi-component beam plasmas are further studied under the fluid theories.The dispersion surface and electromagnetic response of M/W mode are given completely.From the dispersion surface in the kinetic theory,it shows that the relative weak damping arises for the low-frequency branch having the angleq?0°,60°and 90°,and for the high-frequency branch with _rw?[w_cp,300w_cp]having the angleq<60°,which indicates the possible angle and frequency for observed freely-propagating M/W waves.In comparison with the kinetic theory,it proposes that the hot fluid theory is suitable to describe the dispersion relation,the ratio of the parallel to perpendicular magnetic fluctuation _zB/B_?,and the ratio of the electric to magnetic fluctuation E/V_A B.Except the near-parallel low-frequency M/W mode,the hot fluid theory would be used to analyze the ratio between two magnetic fluctuations perpendicular to the wave vector B₁/B₂,the magnetic helicitys,and the ratio of the parallel to perpendicular electric fluctuation _zE/E_?.The cold fluid theory is good at describing the magnetic responses,i.e.,_zB/B_?,B₁/B₂,ands,but it underestimates?,E/V_A B,and E_z/E_?for the obliquely-propagating M/W mode wave.Furthermore,both hot and cold fluid theories perfectly describe the ratio of the longitudinal to transverse electric fluctuation relative to the wave vector E_l/E_p of the obliquely-propagating low-frequency M/W mode.These results provide an indicator how to choose the adequate theory to analyze the observed M/W mode waves in the solar wind and interplanetary shocks.He⁺results in M/W mode waves with medium and large angle asq45°and 75°to be discontinuous.The high-frequency branch is right-hand polarized?iE _y/E_x?29?0?having the angleq5°,45°and 75°.With the existing of plasma beam,the maximum growth rategoccurs in the wavenumberl_pk?29?1 region,while the real frequency _rwis relatively small in the region with no growth rate.Furthermore,the electromagnetic field response E/V_A B and _zB/B_?are large,and _zE/E_??E _l/E_p?B₁/B₂ andsare small.The influence ofbvalues on the dispersion relationship and electromagnetic response in the region with growth rate is greater than that in the region without growth rate.