Magnetic reconnection in Hall MHD simulations including electron inertia.

ANDRÉS NAHUEL; LUIS MARTÍN; DANIEL O. GOMEZ; PABLO DMITRUK

San Francisco

Congreso; American Geophysical Union, Fall Meeting 2012; 2012

American Geophysical Union

Magnetic reconnection is an important physical mechanism of energy conversion in various space plasma physics environments, such as the solar corona or planetary magnetospheres. Theoretical models of magnetic reconnection were first developed within the framework of one-fluid magnetohydrodynamics (MHD), where the Sweet-Parker regime leads to exceedingly low reconnection rates for most space physics problems. Kinetic plasma effects introduce new spatial and temporal scales into the theoretical description, which might significantly increase the reconnection rates. We work within the framework of two-fluid MHD for a fully ionized hydrogen plasma, retaining the effects of the Hall current and electron inertia. More specifically, we performed 2.5 D Hall MHD simulations including electron inertia using a pseudo-spectral code, which yield exponentially fast numerical convergence. Our results show that reconnection takes place in an electron-dominated region, whose spatial scale is given by the electron skin depth. This region is surrounded by a much larger ion-dominated region, with a spatial scale of the order of the ion skin depth. The computed reconnection rates remain a fair fraction of the Alfven velocity, which is much larger than the Sweet-Parker reconnection rate.