Moment equations treatment of the reconnecting mode

Abstract

A mode with azimuthal wave number m = 1 can be excited in a resistive plasma column as a result of reconnection of the magnetic field lines under conditions for which the ordinarily known internal kink mode given by the ideal MHD theory would be stable. In the absence of resistivity, magnetic reconnection would not be allowed and the relevant mode would be singular at a specified radius within the plasma column as in the case of the resistive tearing modes that are found for m ≥ 2. The analysis presented here is based on a set of moment equations that are appropriate for relatively high-temperature and low collisionality regimes. In these regimes, the mode growth rate tends to weaken considerably as the temperature increases and the mode acquires a frequency of oscillation with phase velocity close to the electron diamagnetic velocity, as a result of the effects of finite ion gyroradius and finite drift wave frequency, even in the absence of an equilibrium radial electric field.