Fluid theory of tearing instabilities

Abstract

A fluid theory of tearing instabilities is presented. Recently derived fluid equations, which have the feature of describing adiabatic electron dynamics more completely than the usual transport equations, are employed for this theory. The temperature gradient driven self‐filamentation of a plasma in a uniform magnetic field is described. Temperature gradient driven and magnetically driven ’’collisional’’ and ’’semicollisional’’ drift‐tearing modes are also derived. A comparison with kinetic theories is made; the comparison suggests that the neglect of electron‐electron collisions in kinetic theories of tearing may lead to an overestimate, of appreciable magnitude, of the relative importance of the temperature gradient free energy in driving tearing modes.