Stability of Sheet Pinch

Abstract

The growth rate of the sheet pinch instability is calculated in the small Larmor radius limit using the method of integration along unperturbed orbits. It is found that the instability is driven by a small group of ``resonant'' electrons which cross and drift about the neutral plane having zero velocity along the field lines. The microinstability is absolute and develops fastest for a critical perturbation wavelength, of the order of several times the thickness of the plasma sheet.