PROPAGATION OF HYDROMAGNETIC WAVES NORMAL TO MAGNETIC FIELD IN PRESENCE OF CURRENTS

Hydromagnetic waves propagated normal to the magnetic field in the presence of a steady current density are investigated. Current densities and parameters characteristic for parts of the ionosphere and magnetosphere are considered. The current density is introduced into the macroscopic equations by assuming drift velocities of the electron and ion fluids. Solutions of the dispersion relation which follow from these equations are considered for special cases. Propagation parallel to the magnetic field has been considered in a previous publication. Two special cases for propagation normal to the magnetic field are considered in this paper. In the first case, propagation normal to the magnetic field with currents along the propagation vector is considered. Solutions of the dispersion relation for this case correspond to stable waves. The second case deals with propagation normal to the magnetic field with currents normal to both the propagation vector and the magnetic field. Solutions of the dispersion relation for the second case indicate a convective instability arising from the presence of the transverse currents. The waves may be amplified in this case. Some numerical results for data representative of the ionosphere and magnetosphere are given. © 1969.