REPRESENTATION OF STABILITY INTEGRAL FOR POLOIDAL MAGNETIC-FIELD CONFIGURATIONS USING INVERTED VARIABLES

The convective stability integral U = integral B(-1)dl for a poloidal magnetic field configuration in a low-pressure plasma is derived as U =1/8d(2)/d psi(2) integral r(4)(psi, chi)d chi, where psi is the flux coordinate; chi is the magnetic potential (B = del chi); represents th e magnetic line distance from the axis, satisfying the Rosenbluth-Varm a equation partial derivative/partial derivative psi( r partial deriva tive r/partial derivative psi)+partial derivative/partial derivative c hi(1/r partial derivative r/partial derivative chi) = 0. These variabl es, adequate to the problem of plasma stability versus convective pert urbations, are used to find MHD-stable axisymmetric straight hollow co nfigurations.