Evolution of Subsonic Shock Waves Associated with Reconnection Jets in Earth’s Magnetotail

Abstract

Motivated by the signatures of nonlinear electrostatic waves observed by the Magnetospheric Multiscale spacecraft mission in reconnection jet regions of Earth's magnetotail, we have explored the dynamical features of ion-acoustic shock waves in the magnetotail. In this investigation, we have examined the dynamics and characteristics of ion-acoustic subsonic shock waves in non-Maxwellian space plasma comprising of two counterstreaming ion beams with suprathermal electrons, assumed to follow a kappa (κ) distribution. A reductive perturbation technique has been adopted to establish an evolution equation for small amplitude electrostatic shock structures. Importantly, subsonic waves only exist when the beam velocity exceeds a certain threshold, beyond which supersonic and subsonic waves may coexist. The combined effects of the beam velocity and the non-Maxwellian electron statistics have been analyzed to examine the characteristics of subsonic shock waves. Both symmetric and asymmetric (in relative beam density) models have been considered, leading to distinct possibilities in the evolution of subsonic shock waves. The findings of the investigation will help unfold the relatively unexplored dynamical characteristics of subsonic shock waves that may form and propagate in the magnetosphere.

Oblique Electrostatic Solitary and Supersolitary Waves in Earth’s Magnetosheath

“…Suprathermal distributions have been applied in modeling particle populations not only in the solar wind (Armstrong et al 1983) but also within planetary magnetospheres, including Earth's, Saturn's, and Jupiter's (Leubner 1982;Singh et al 2020Singh et al , 2021Singh et al , 2022Singh et al , 2023Singh et al , 2024Kakad et al 2022;Varghese et al 2022Varghese et al , 2023.…”