Solitary kinetic Alfvén waves in nonextensive electron-positron-ion plasma

Abstract

In low but finite β (thermal to magnetic pressure ratio) collisionless nonextensive electron-positron-ion plasma, we have derived linear dispersion relation of kinetic Alfvén waves (KAWs) and have also investigated solitary KAWs through Sagdeev pseudopotential approach in small amplitude limit. Linear analysis of KAWs shows a decrease in frequency of the wave with increase in each of the parameters, viz. r (equilibrium positron-to-ion density ratio), α (electron-to-positron temperature ratio) and q (nonextensive parameter). Nonlinear analysis of KAWs reveals that the nonextensive plasma model considered here supports only compressive solitary waves at sub-Alfvénic speeds. The effects of q, r, α and a (soliton parallel velocity) on the characteristic properties of solitary KAWs are depicted in graphical plots. The results of our present investigation may have relevance to the understanding of low-frequency electromagnetic noises/localized fluctuations in strongly magnetized electron-positron-ion plasmas having nonextensive electrons and positrons.