Rotation Waves and Turbulence in a Multispecies Plasma

Summary form only given. We show that in an electron-light ion-heavy ion plasma, the light component can rotate with a frequency, Omega
_r
= (Zn
_H
/n
_e
)Omega
_L
where n
_H
and n
_e
are their densities, Z is the heavy ion charge state, and Omega
_L
is the light ion gyro-frequency. There is a current perpendicular to the magnetic field due to the light ion and electron EtimesB 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 rotation of the lighter fluids. Omega
_r
falls in-between the light and heavy ion cyclotron frequencies. The rotation introduces a new time scale and can significantly affect the waves with frequencies close to Omega
_r
. This is analogous to the cyclotron phenomenon but distinct from it. We show that for the rotation waves, the wave energy is mainly in the kinetic (rotation) energy of the light ion fluid which affects the large-scale MHD properties; in particular, the character of turbulence. For example, the nonlinear MHD wave evolution near Omega
_r
is governed by a nonlinear Schrodinger equation. For long wavelengths (kVA = Omega
_r
) the dispersion relation becomes isomorphic to the electrostatic Langmuir wave dispersion relation. The interaction of the fast rotation time-scale with the slow heavy ion magnetosonic time-scale is achieved via ponderomotive force resulting in the formation of long wavelength condensates and strong turbulence. This implies that the turbulence spectrum is likely to be determined by the appearance and collapse of solitons into structures with scale size L~VA/Omega
_r
. We also show that nonlinearly the waves near Omega
_r
can support large magnetic gradients and lead to plasma energization. Applications to space and astrophysical environments will be discussed