Study of Equilibrium and Stability of Plasma in Heliotron Magnetic Field

Abstract

Equilibrium and stability problems of plasma in the Heliotron magnetic field are discussed under the assumption that the plasma behaves as a hydromagnetic fluid and its pressure is much less than magnetic pressure. Both plasma pressure and diamagnetic current satisfying the equilibrium conditions are analyzed in the case where the plasma carries only a diamagnetic jθ current and not a jz current due to an external electric field. Also by using the curvilinear coordinate system peculiar to Heliotron magnetic field, the stability condition for the flute type instability is discussed according to the energy principle which was investigated by I.B. Bernstein et al.. It is concluded that Heliotron magnetic field provides the equilibrium of plasma inside the separatrix and the plasma in this field is stable against the interchange instability under the proper gradient of plasma pressure.