Ion-acoustic shocklets in F-region of ionosphere with non-Maxwellian electrons

Abstract The evolution and propagation characteristics of ion-acoustic (IA) shocklets are examined in an unmagnetized collisionless plasma, comprised of warm ions and non-Maxwellian (Kappa/Cairns) electrons. Solving the fluid equations and using the frameworks of diagonalized-matrix/changing variable techniques, a nonlinear evolution equation is obtained, which admits dispersionless/dissipationless evolution of IA shocklets. Numerical analyses have also confirmed the excitation/deformation of IA shocklets and the wave overtaking/breaking effects at time for nonlinear coupling of potential field. It is found that superthermal (Kappa distributed) electrons can enhance the overtaking/breaking of IA perturbations in comparison with nonthermal Cairns distributed electrons that lead to less steepened potential field to stabilize IA excitations against the nonlinear steepening. Finite ion temperature has significant impact on the wave coupling to lead the profiles of IA shocklets ahead. This study is important to understand the physical mechanism for excitation and deformation of IA shocklets relevant to the F-region of Ionosphere.