On the two-fluid modification of the resistive tearing instability

We consider the two-fluid resistive tearing mode for an inviscid highly conducting (a large Lundquist number S) plasma in a sheared force-free magnetic field. It is shown that under the "constant-psi" approximation there are four possible instability regimes, each of which corresponds to the specific domain in the parameter space (beta,d(i)). Here, beta is a standard plasma thermal pressure parameter, while d(i)equivalent to c/(omega(pi)l) is the normalized ion inertial skin depth, with l being the shear length of the magnetic field. A qualitative analysis emphasizing when and why the transitions from one regime to another occur is also provided. (c) 2007 American Institute of physics.