Effect of orbital angular momentum on electron acoustic waves in double‐Kappa plasma

Abstract

Abstract Kinetic theory of electron acoustic waves (EAWs) in the presence of wave angular momentum has been derived to study the effect of wave angular momentum on the propagation of EAWs in a non‐Maxwellian plasma. Both types of electrons (hot and cool) are modeled as Kappa‐distributed velocity distribution functions. The theory is also applied to Saturn's magnetosphere where these kinds of distribution functions are commonly found. It is seen that the presence of wave angular momentum in the model has a significant effect on the existence of the regions where EAWs are weakly damped. The effect of wave angular momentum on EAWs is studied by defining a parameter η = k /( l q θ ), which is the ratio of the planar wave number to the azimuthal wave number. The wave is purely planar if . The weakly damped region of EAWs depends strongly on this parameter in addition to other parameters such as hot electron spectral index κ h , cool electron spectral index κ c , the fraction of hot electrons, and hot to cool electrons temperature ratio. The results also show the effect of η on the propagation of EAWs in various regions of Saturn's magnetosphere.