Interpretation of double layers and associated electric field structures in earth's magnetosphere based on (r,q) and nonextensive ɋ-distributions

Double layers (DLs) and associated parallel electric fields have been considered as the drivers of the parallel currents and responsible for the particle acceleration in space plasmas. DLs are Debye scale nonlinear structures that are typically one-dimensional, stationary, and collisionless potential structures. In this paper, we studied double layers and parallel electric field structures associated with the kinetic Alfvén waves in a low beta electron-ion plasma. We considered electrons to follow (r,q) and nonextensive ɋ-distributions and incorporated the modified temperature through plasma beta in our fluid model. We found that both the compressive and rarefactive double layers can be obtained in our model and are strongly dependent on the nonthermal spectral indices. We applied our model to the observations of DLs and associated parallel electric fields and showed that the numerical results from our model successfully interpret the observation of DLs and associated parallel electric field structures from the Earth's plasma sheath boundary layers, in particular, and in other space plasma regions, in general.