PROFILE STABILIZATION OF TILT MODE IN A FIELD-REVERSED CONFIGURATION

The possibility of stabilizing the tilt mode in field-reversed configu rations without resorting to explicit kinetic effects such as large io n orbits is investigated. Various pressure profiles, P(PSI), are chose n, including ''hollow'' profiles, where current is strongly peaked nea r the separatrix. Numerical equilibria are used as input for an initia l value simulation, which uses an extended magnetohydrodynamic (MHD) m odel that includes viscous and Hall terms. Tilt stability is found for specific hollow profiles when accompanied by high values of separatri x beta, beta(sep). The stable profiles also have moderate to large elo ngation, racetrack separatrix shape, and lower values of sBAR, average ratio of Larmor radius to device radius. The stability is unaffected by changes in viscosity, but the neglect of the Hall term does cause s table results to become marginal or unstable. Implications for interpr etation of recent experiments are discussed.