Reconnection current sheet structure in a turbulent medium
- 1Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon SK S7N 5E2, Canada
- 2Department of Physics and Astronomy, McMaster University, Hamilton ON L8S 4M1, Canada
- 3Department of Applied Mathematics and Statistics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
- 4Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão, 1226 – Cidade Universitária, CEP 05508-090, São Paulo/SP, Brazil
- 5Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706, USA
- 6Department of Mechanical Engineering, McMaster University, Hamilton ON L8S 4M7, Canada
Abstract. In the presence of turbulence, magnetic field lines lose their dynamical identity and particles entrained on field lines diffuse through space at a rate determined by the amplitude of the turbulence. In previous work (Lazarian and Vishniac, 1999; Kowal et al., 2009; Eyink et al., 2011) we showed that this leads to reconnection speeds which are independent of resistivity. In particular, in Kowal et al. (2009) we showed that numerical simulations were consistent with the predictions of this model. Here we examine the structure of the current sheet in simulations of turbulent reconnection. Laminar flows consistent with the Sweet-Parker reconnection model produce very thin and well ordered currents sheets. On the other hand, the simulations of Kowal et al. (2009) show a strongly disordered state even for relatively low levels of turbulence. Comparing data cubes with and without reconnection, we find that large scale field reversals are the cumulative effect of many individual eddies, each of which has magnetic properties which are not very different from turbulent eddies in a homogeneous background. This implies that the properties of stationary and homogeneous MHD turbulence are a reasonable guide to understanding turbulence during large scale magnetic reconnection events. In addition, dissipation and high energy particle acceleration during reconnection events take place over a macroscopic volume, rather than being confined to a narrow zone whose properties depend on microscopic transport coefficients.