PROPAGATION CHARACTERISTICS OF WAVE-PACKET IN NONUNIFORM MAGNETIC-FIELDS

Experimental observations on a wave packet in a positive column of hel ium discharge with magnetic fields are reported. The wave packet is a kind of ionization wave and is created by applying voltage pulses to a mesh grid. When an axial non-uniform magnetic field is applied to a p ositive column, the plasma parameters change inhomogeneously near the magnetic coil. So various characteristics (amplitude, frequency, wavel ength and so on) of the wave packet are changed at the both sides of t he coil. The wavelength of the wave making up the wave packet varies c ontinuously with a magnetic field. On the contrary, its amplitude and frequency vary remarkable near the magnetic coil, as a strong magnetic field is applied.