Equilibrium and nonlocal stability properties of collisionless theta-pinch plasmas

The equilibrium and nonlocal stability properties of collisionless, high-β, theta-pinch plasmas are investigated using a Vlasov description and using a two-fluid description. The equilibrium configuration is assumed to be an infinitely long, azimuthally symmetric plasma column with currents purely in the azimuthal direction and magnetic field purely in the axial direction. For the stability analysis, primary emphasis is on the frequency regime OMEGA/sub i/less than parallel bar ω parallel bar less than OMEGA/sub e/. The general procedure for constructing high-β theta-pinch equilibria within the framework of the steady-state Vlasov-Maxwell equations is discussed. Properties are calculated for a number of sharp-boundary and diffuse-boundary, rigid-rotor Vlasov equilibria and general equilibrium relations that pertain to the entire class of rigid-rotor equilibria are presented. A method is presented for reconstructing the distribution function of a rigid-rotor equilibrium if the temperature, rotational frequency, and either the density or magnetic field profile is known. Equilibrium properties of theta-pinch plasmas are also investigated using a two-fluid description and a comparison is made between the two-fluid and ideal MHD formulations. A two-fluid model is developed to describe the linear electrostatic stability of cylindrically symmetric plasmas with axial magnetic fields