Effect of kappa distribution on the damping rate of the obliquely propagating magnetosonic mode

Data from spacecrafts suggest that space plasma has an abundance of suprathermal particles which are controlled by the spectral index κ when modeled on kappa particle velocity distribution.In this paper,considering homogeneous plasma,the effect of integer values of κ on the damping rate of an obliquely propagating magnetosonic (MS) wave is studied.The frequency of the MS wave is assumed to be less than ion cyclotron frequency,i.e.,ω 《 ωi.Under this assumption,the dispersion relation is investigated both numerically and analytically,and it is found that the real frequency of the wave is not a sensitive function of κ,but the imaginary part of the frequency is.It is also shown that for those values of κ where a large number of resonant particles participate in wave-particle interaction,the wave is heavily damped,as expected.The possible application of the results to the solar wind is discussed.