Open AccessMagnetosheath Jets and Plasmoids: Characteristics and Formation Mechanisms from Hybrid Simulations
Author(s) -
Luis Preisser,
X. BlancoCano,
Primož Kajdič,
David Burgess,
Domenico Trotta
Publication year - 2020
Publication title -
the astrophysical journal. letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.639
H-Index - 201
eISSN - 2041-8213
pISSN - 2041-8205
DOI - 10.3847/2041-8213/abad2b
Subject(s) - plasmoid , magnetosheath , physics , bow shock (aerodynamics) , shock (circulatory) , ram pressure , jet (fluid) , mechanics , shock wave , magnetohydrodynamics , plasma , solar wind , oblique shock , magnetic field , computational physics , astrophysics , magnetic reconnection , magnetopause , nuclear physics , star formation , medicine , stars , quantum mechanics
Magnetosheath jets and plasmoids are very common phenomena downstream of Earth’s quasi-parallel bow shock. As the increase of the dynamic pressure is one of the principal characteristics of magnetosheath jets, the embedded paramagnetic plasmoids have been considered as an special case of the former. Although the properties of both types of structures have been widely studied during the last 20 years, their formation mechanisms have not been examined thoroughly. In this work we perform a 2D local hybrid simulation (kinetic ions – fluid electrons) of a quasi-parallel ( θ Bn = 15°), supercritical ( M A = 7) collisionless shock in order to study these mechanisms. Specifically, we analyze the formation of one jet and one plasmoid, showing for the first time that they can be produced by different mechanisms related to the same shock. In our simulation, the magnetosheath jet is formed according to the mechanism proposed by Hietala, where at the shock ripples the upstream solar wind suffers locally less deceleration and the flow is focused in the downstream side, producing a compressed and high-velocity region that leads to an increase of dynamic pressure downstream of the shock. The formation of the plasmoid, however, follows a completely new scenario being generated by magnetic reconnection between two plasma layers with opposite B -field orientation in the region just behind the shock.