Astrophysical Implications of Turbulent Reconnection: from cosmic rays to star formation

Abstract

Turbulent reconnection allows fast magnetic reconnection of astrophysical magnetic fields. This entails numerous astrophysical implications and opens new ways to approach long standing problems. I briefly discuss a model of turbulent reconnection within which the stochasticity of 3D magnetic field enables rapid reconnection through both allowing multiple reconnection events to take place simultaneously and by restricting the extension of current sheets. In fully ionized gas the model in Lazarian and Vishniac 99 predicts reconnection rates that depend only on the intensity of turbulence. In partially ionized gas a modification of the original model in Lazarian, Vishniac and Cho 04 predicts the reconnection rates that, apart from the turbulence intensity depend on the degree of ionization. In both cases the reconnection may be slow and fast depending on the level of turbulence in the system. As the result, the reconnection gets bursty, which provides a possible explanation to Solar flares and possibly to gamma ray busts. The implications of the turbulent reconnection model have not been yet studied in sufficient detail. I discuss first order Fermi acceleration of cosmic ray that takes place as the oppositely directed magnetic fluxes move together. This acceleration would work in conjunction with the second order Fermi acceleration that is caused by turbulence in the reconnection region. In partially ionized gas the stochastic reconnection enables fast removal of magnetic flux from star forming molecular clouds.