Parallel Electric Field and Double Layers at Non-Maxwellian Effective Temperature Scales in Near Earth Space Plasmas

Magnetic reconnection interlinks different regions of plasmas by converting magnetic energy into plasma heating and energization of particles. It causes abrupt changes in the temperature, density, field strength and flow speed. The physical mechanism behind charge particle energization during magnetic reconnection is best explained by the concept of double layers (DLs) and associated parallel electric fields. In-situ observations of reconnection sites by Magnetospheric Multi Scale (MMS), THEMIS and FAST have confirmed that charge particle energization in these regions is associated with large parallel electric fields in auroral regions, Earth’s plasma sheet and separatrix region of Earth’s magnetosphere. The reported literature motivated us to investigate double layers and associated electric field at the reported sites by using multi-fluid theory for electron-ion plasma and employing fully nonlinear Sagdeev potential approach. We have considered the ion inertial effect whereas electrons are assumed to be non-Maxwellian following (r, q) distribution function. In particular, parallel electric fields associated with Alfvenic double layer have been investigated at non-Maxwellian effective temperature scales and then compared with the observations. We have seen that the characteristics of DLs associated with the kinetic Alfvén waves are significantly modified due to the nonthermal parameters r and q, propagation angle 𝜃, and Alfvénic Mach number 𝑀_A. Our current study supports both the compressive and rarefactive double layer structures.