HR: 0830h
AN: SM31C-1129    [PDF]
TI: Rotation Waves and Strong Turbulence in a Multi-Component Plasma*
AU: * Ganguli, G I
EM: gang@ppd.nrl.navy.mil
AF: Plasma Physics Division, Code 6794, Naval Reseasch Laboratory, Washington, DC 20375 United States
AU: Rudakov, L L
EM: rudakovl@wam.umd.edu
AF: Berkeley Scholars Inc., P.O. Box 852, Springfield, VA 22150 United States
AB: We show that in a three-component plasma, e.g., electrons, ions, and negatively charged dust, such that $n_d \ll n_i \sim n_e$, the light components (electrons and ions) can rotate rigidly with a frequency, $\Omega_r=Zn_d\Omega_i/n_e$, where $n_{i,e,d}$ are ion, electron, and dust densities, $Z$ is the dust charge state, and $\Omega_i$ is the ion gyro-frequency. The origin of this rotation is shown to be due to $n_i \neq n_e$, so that there is a current perpendicular to the magnetic field due to ion and electron ${\rm\bf E} \times {\rm\bf B}$ drift, which induces an electric field in the direction of the current. Hence the plasma is subject to electric forces simultaneously in the two orthogonal directions perpendicular to the magnetic field resulting in a rotation. A new low-frequency resonance at $\omega=\Omega_r$ appears in the MHD limit and affects the dispersion character of the electromagnetic waves. The magnetosonic dispersion relation [$\omega^2=\Omega_r^2+k^2(V_A^2+C_s^2)$, where $V_A$ and $C_s$ are the Alfven and ion sound speeds] is modified and becomes isomorphic to the electrostatic Langmuir wave dispersion relation. We find that the interaction of the fast rotation time-scale with the slow magnetosonic time-scale can be achieved via ponderomotive force and this could lead to a nonlinear Schrodinger equation for the magnetosonic branch. We also find that it is possible to develop nonlinear structures at very large MHD scales with scale-size $L\sim{V}_A/\Omega_{r0}\sim(c/\omega_{pi})(n_e/Zn_d)(n_i/n_e)^{1/2}$, where $\omega_{pi}$ is the ion plasma frequency, which could be comparable to astrophysical dimensions. Linear stability and nonlinear structures that could arise in the frequency regime $\omega\sim\Omega_r$ will be discussed along with some space and laboratory applications. *Work supported by NASA and ONR.
DE: 6984 Waves in plasma
DE: 7827 Kinetic and MHD theory
DE: 7863 Turbulence
DE: 7871 Waves and instabilities
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting