Microwave processes in the octupole galathea

Results are presented from experimental studies of electromagnetic emission and plasma oscillations in the plasma-frequency range in the Octupole Galathea confinement system. Experiments are performed in the electric-discharge mode at low magnetic fields (the barrier field is 0.002-0.01 T); the working gas is argon or hydrogen. It is found that the most intense microwave oscillations at frequencies of 1-5 GHz are excited near the plasma axis and in the magnetic-barrier region. The oscillations are excited by the discharge current and decay after the voltage is switched off. The experiments show that microwave oscillations excited in the magnetic-barrier region are responsible for the small value of the energy confinement time in the system