Slow shock formation and structure with sub‐Alfvénic shear flow in magnetic reconnection

Abstract

[1] Slow shock formation and structure associated with magnetic reconnection are investigated in the presence of sub-Alfvénic shear flow using a compressible resistive MHD model. It is found for the first time that one or two pairs of the slow shocks are formed in the inflow region away from the reconnection separatrices within compressible resistive MHD. The distributions of the slow shocks depend largely on the plasma beta and the shear flow velocity that lead to the increase of magnetic reconnection rate. One pair of the slow shocks is formed for b = 0.2 and two pairs of the slow shocks are generated for b = 1.0 with the shear flow velocity in the range 0.6 V A to 0.9 V A . For high plasma beta (b = 5.0), there is no slow shock formed outside the reconnection separatrices. The results can be applied to interpret slow shock observations at the dayside magnetopause.

Bursty magnetic reconnection under slow shock‐generated whistler waves

“…For the case without the Hall effect ( d i = 0.0), it is clearly shown that there are two pairs of discontinuity structures that have been identified as slow shocks by Li et al . []. The shock (in red color) near the reconnection region is a weak slow shock.…”

“…Shear flows are very commonly observed, such as in the magnetopause boundary, the solar wind, and tokamaks, and are believed to involve the tearing mode. The shear flow can affect both shock formation and magnetic reconnection [ La Belle‐Hamer et al ., ; Li and Ma , ; Zhang et al ., ; Li et al ., ; Shen et al ., ]. The influence of sub‐Alfvenic shear and super‐Alfvenic flows on magnetic reconnection is rather different.…”

“…Based on resistive MHD simulation of the magnetic reconnection in the presence of the sub‐Alfvenic shear flow, Li et al . [] found that the slow shocks are observed in the inflow region or outside the reconnection separatrices. Zhang et al .…”

Shock formation and structure in magnetic reconnection with a streaming flow

“…The fast shear flow exists in solar wind, magnetopause boundary, etc. The shear flow can exert conspicuous effects on both magnetic reconnection and shock generation 12 – 21 . The role of a sub-Alfvénic shear flow in magnetic reconnection is very different from that of a super-Alfvénic shear flow.…”

Slow shock and rotational discontinuity in MHD and Hall MHD models with anisotropic pressure

“…Recently, the structure of SSs has also been studied based on the 2‐D MHD and particle simulations with isotropic [ Li et al ., ] and anisotropic pressures [ Hung et al ., ; Liu et al ., ; Higashimori and Hoshino , ; Hirabayashi and Hoshino , ; Higashimori and Hoshino , ]. In particular, the 2‐D gyrotropic MHD simulations have shown that anomalous reconnection layer consisting of an SS followed by the RD may possibly form in a current sheet with p ∥ > p ⊥ [ Hung et al ., ] as predicted by our earlier 1‐D simulations [ Hau and Hung , ] (referred to as Paper 1).…”