TEARING INSTABILITIES IN MULTIPLE CURRENT SHEETS FOR CURRENT-DEPENDENT RESISTIVITY MODELS

A generalized analytical treatment of the resistive tearing mode in mu ltiple current sheets for current-dependent electrical resistivities i s given. This generalization allows for taking into account anomalous dissipation caused by current-driven microturbulence. The growth rates of the mode are found to be larger than the growth rates for constant resistivity. Numerical simulations show the linear and nonlinear deve lopment of the instability, where, in particular, the assumption of pe riodic configurations necessary in the analytical treatment can be rel axed. The results indicate that reconnection in neighboring magnetic f lux systems mainly results in Ohmic heating and small tongue outflow r ather than plasmoid-like eruptions. (C) 1997 American Institute of Phy sics. [S1070-664X(97)01111-7].