Drift-Alfve'n vortices with finite ion gyroradius and electron inertia effects

A two-fluid plasma model is used to analyze drift-Alfven vortices in a magn etized, inhomogeneous, warm plasma. This low-beta model retains the effects of finite electron mass and of finite ion gyroradii. The vortices are desc ribed by two potentials: the electrostatic potential and one component of t he vector potential. The background plasma is assumed to have locally a lin ear density profile. Solutions in the form of dipoles, which propagate with constant velocity across a strong, uniform magnetic field, are analyzed. A general dispersion relation between the eigenvalues inside and outside the separatrix is derived. The analysis of this dispersion relation and of the spatial vortex structure leads to a general classification of two-potentia l vortices. Explicit solutions are presented for dipole vortices in the lim it of zero electron inertia where finite gyroradius effects are retained an d in the limit of cold ions where finite electron mass is taken into accoun t. (C) 1999 American Institute of Physics. [S1070-664X(99)03403-5].