Study of plasma flow reversal in the near-Earth plasma sheet using numerical computations

Koji Kondoh,Tohru Shimizu

doi:10.1186/s40623-014-0147-1

Abstract

Tailward flow in the near-Earth plasma sheet associated with a rebound of the earthward bursty bulk flow (BBF) is investigated using three-dimensional magnetohydrodynamics simulations of magnetic reconnection in the magnetotail on the basis of the spontaneous fast reconnection model. In order to investigate the properties of this tailward flow, virtual satellites are located at different positions in the plasma sheet within the simulation region, so that we can directly observe the temporal variations of plasma quantities in accordance with the growth and preceding the flow reversal associated with the magnetic reconnection. The time profile of the plasma flow velocity in the course of the BBF depends on the satellite position. Furthermore, the time profile of the magnetic field strength in the course of the reverse flow depends on the satellite position in the dawn-dusk direction. As a result of the rebound of the earthward flow, the accumulation of the plasma density and the plasma pressure is observed at any position in the plasma sheet during the interval between the BBF and the reverse flow.

Highlights

Magnetic reconnection plays an essential role in large dissipative events observed in space plasmas
We have proposed the spontaneous fast reconnection model and demonstrated by magnetohydrodynamic (MHD) simulations that the fast reconnection mechanism can be realized as an eventual solution by a nonlinear instability due to the positive feedback between current-driven anomalous resistivities and reconnection flows (Kondoh et al 2011; Ugai and Kondoh 2006)
We focus on the flow reversal associated with the bursty bulk flow in the near-Earth plasma sheet

Summary

Introduction

Magnetic reconnection plays an essential role in large dissipative events observed in space plasmas. Flow reversal In order to investigate the time variation of the magnetic loop and plasma flow, Figure 2 shows the plasma flow velocity, V (arrows), and the magnetic field component, Bz (black solid lines), on the x − y plane at t = 36 (a), t = 42 (b), t = 48 (c), and t = 54 (d).

Results

Conclusion