Modification of the tearing mode growth rate by the presence of a stochastic magnetic field

We have studied the effect of a stochastic magnetic field on the growth of a tearing mode. An analytic solution is given for the case in which the stochastic magnetic field is static. In that case, an unstable tearing mode is further destabilized (stabilized) if the Δ' values of the nonlinearly driven modes are positive (negative). This mechanism explains the destabilization of the (m = 3; n = 2) tearing mode observed in nonlinear three-dimensional calculations