Topic/Type: 2.1 MHD, EHD & other fluid methods, Poster

Very high resolution MHD simulation of magnetic reconnection at high magnetic Reynolds numbers

T. Miyoshi1, K. Kusano2

1 Hiroshima University, Higashi-hiroshima, Japan
2 Nagoya University, Nagoya, Japan

We present a very high resolution resistive magnetohydrodynamic (MHD) simulation of the nonlinear tearing mode for high magnetic Reynolds numbers . Therefore, a very high resolution numerical scheme is newly developed based on Harten-Lax-van Leer-Discontinuities (HLLD) approximate Riemann solver [Miyoshi and Kusano 2005]. In particular, a two-dimensional Harris current sheet model with a uniform resistivity is adopted as an initial condition in order to achieve as high as possible. Thus, high MHD reconnection can be successfully simulated.

Simulation results at high show that multiple small scale plasmoids are intermittently created by secondary tearing instabilities in a nonlinearly developed thin current sheet and ejected by super-fast-magnetosonic speed, while at not-so-high only the primary tearing instability grows steadily. We find that the reconnection rate at high is greatly enhanced with the intermittent plasmoid ejections. The results strongly suggest that the nonlinearity in MHD at very high could work to make fast magnetic reconnection automatically through the self-destabilization of smaller scale instabilities.