Magnetic field effects on the backward branch of a surface ion-cyclotron wave

The effects of magnetic field strength on the backward branch of a surface ion-cyclotron wave are investigated in a semi-bounded magnetized plasma. The dispersion relation of the backward mode of the surface ion-cyclotron wave is obtained by the plasma dielectric function with the specular reflection boundary condition. The result shows the existence of the long wavelength backward mode in the surface ion-cyclotron wave. The frequency of the wave is found to be decreased with increasing wavenumber. It is also found that the wave frequency increases with an increase in the ratio of the electron gyrofrequency to the electron plasma frequency, i.e., with increasing the magnetic field strength. In addition, the group velocity of the surface ion-cyclotron wave decreases with decreasing the magnetic field strength