The effect of magnetic field-aligned flow with a transverse flow velocity gradient (velocity shear) on the generation of electrostatic ion cyclotron waves is studied analytically by using kinetic formalism. It is shown that flow shear not only modifies the frequency and growth rate of a known current-driven electrostatic ion cyclotron instability (CDEIC), but is the source of the development of specific kinetic and hydrodynamic shear-flow-driven ion cyclotron instabilities at the levels of current along the ambient magnetic field, which is subcritical for the development of the CDEIC instability.
The equation of motion of charged plasma particles in a homogeneous magnetic field and in an inhomogeneous stochastic electric field with a characteristic oscillation frequency much lower than the electron cyclotron frequency and much higher than the ion cyclotron frequency is solved. The diffusion motion, as well as the drift of ions and guiding center of electrons, due to the inhomogeneity of the stochastic electric field, is considered. The obtained values of the diffusion coefficient and drift velocity are used in the Fokker-Planck equation to determine the stationary distribution of the plasma density due to the effect of an inhomogeneous stochastic field.
An extension of hydrodynamic D'Angelo mode of inhomogeneous sheared plasma flow along the magnetic field into the short wavelength range, where the hydrodynamic treatment is not valid, has been considered. We find that D'Angelo mode in this wavelength range is excited by inverse ion Landau damping and is a shear flow driven ion-kinetic mode.
Abstraet-lk ion cyclotron turbulence theory of rotating plasmas in crossed fields is considered. This turbulence is due to the instability of short-wavelength (k,p, > I) modified ion cyclotron waves (ion Bernstein modes). This instability is caused by an azimuthal drift of electrons with respect to ions with a relative velocity A I J below the ion thermal velocity tiyi.The generalized weak turbulence theory and quasilinear theory as well as the strong turbulence theory accounting for cyclotron resonance broadening due to the random walk of ions in a perturbed electric field are constructed. Cylindrical waves, the radial dependence of which is determined by the Bessel function J,(k,r) with m >> 1, serve as elementary perturbations of electrostatic potential in these theories. Induced scattering of ion cyclotron cylindrical waves on bare ions is shown to be the main mechanism, totally suppressing higher-order modes (o a no,,,n > 2) ion cyclotron waves in the weak-turbulence regime at
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