Dynamics of electromagnetic drift-flute waves in high-beta plasmas in the presence of sheared plasma flows

Summary form only given. Investigation of the mechanisms of penetration of high-beta plasma flows across the magnetic field is important for numerous applications. These studies are relevant to the physics of z-pinches, space physics (e.g. solar wind), and astrophysics (e.g. supernovae). Laboratory experiments designed and performed at the Nevada Terawatt Facility (I.R. Presura et. al., 2007) have focused on studying the propagation of a plasma plume across a magnetic field. These experiments have revealed instabilities growing at the plasma-field interface that could be explained by the excitation of electromagnetic flute drift modes in a high-beta plasma. In certain cases convective structures similar to Kelvin-Helmholtz instability have been identified. In support of these experiments we are developing models that can explain the observed plasma turbulence. We are interested in the excitation of drift-flute waves in a high-beta plasma flow with velocity shear. We consider the plasma flowing perpendicular to the magnetic field directed along the z-direction, and with a shear in the direction perpendicular to both the magnetic field and the plasma velocity. Magnetic field curvature effects are emulated through a gravitational acceleration. In order to investigate the linear growth and nonlinear dynamics of the electromagnetic drift waves, a nonlinear set of equations for the electrostatic potential, magnetic field and density perturbations is derived, using the two-fluid equations in the low-frequency approximation, and taking into account finite ion Larmor radius effects. It is shown that the hydrodynamic approach can be used to correctly describe the dispersion of the electromagnetic drift waves, even though a kinetic approximation would be required in this case (V.I. Sotniviko et. al. 2009). The nonlinear dynamics and interaction of these modes can be analyzed using numerical simulations.