Excitation of kinetic Alfvén waves by streaming ions in a dusty magnetoplasma with generalized (r, q) distribution function

Abstract

We investigate the parallel streaming effects on the dispersion characteristics of a kinetic Alfvén wave (KAW) in a low 𝛽 dusty magnetoplasma. To analyse the influence of streaming ions obeying generalized (r, q) distribution function, hot and magnetized electrons, and mobile charged dust, a theoretical approach has been used for the instability analysis by employing two potential theories. A lin ear kinetic dispersion relation of Alfvén waves is derived, whose solutions are used to interpret the numerical and analytical results. The solutions of disper sion relation indicate that the characteristics of KAWs are transformed when generalized (r, q) distribution function is employed instead of its Maxwellian counterpart. We also found that the unstable modes have a strong dependence on spectral indices r and q, dust parameters, and plasma 𝛽. For the excitation of KAWs, the streaming velocity has been observed to be within the sub-Alfvén range, whereas when it extends to the super-Alfvén range, the growth rates are significantly suppressed. The observations further show that an ambient magnetic field and superthermal particles inhibit the growth of an electromag netic wave to a significant degree and have a stabilizing effect on the wave mode, whereas an increasing concentration of low-energy particles contributes to enhancing growth rates.