Effect of switching-off a magnetoplasma medium on a whistler wave in a cavity: FDTD simulation

A whistler wave in a cavity filled with a magnetoplasma is strongly effected when the magnetoplasma is switched-off. The collapse of the magnetoplasma can be due to the switching-off the ionization source or due to the switching-odd the source of the background quasistatic magnetic field. In the former case the whistler wave is converted to a power-intensified higher frequency wave (with an order of magnitude upshift of the frequency). In the later case the whistler wave is converted to a wiggler magnetic field.; Finite Difference Time Domain (FDTD) technique is used to study the effect of the following parameters: the rate of collapse, spatial plasma profile, collision frequency as well as the switching angle.; Another related problem is also solved using FDTD technique. In this case magnetoplasma is switched-on. The medium in the one-dimensional cavity (cavity width in z-direction) is free space and the source wave is a standing wave with the electric field in the x-direction. A static magnetic field is present in the y-direction. A plasma is switched-on in the presence of this static magnetic field. The output waves are extraordinary waves (X waves). An earlier study used a model of sudden switching-on the plasma medium assuming a step profile for the electron density. In this thesis, a more practical problem is studied by assuming a finite rise time for the electron density. The effect of the rise time on the output waves is the focus of this study. FDTD technique is used to study the evolution of the electric and magnetic field of the output waves during the transition period. The results of this study are given in Appendix.