The collisional tearing mode instability in a quasi-stational plasma

The behaviour of a small perturbation in the diffuse neutral sheet is analysed in a frame of MHD equations. It is shown that the normal magnetic component perpendicular to the current sheet does not contribute to the stability of the tearing instability in both the cases of high coductivity limit and low conductivity limit. The plasma flow expanding along the sheet can effectively stabilize the tearing instability. The nonlinear stage of this mode is estimated. It is shown that the secondary stationary flow with a hyperbolic pattern is structed. (author)