Cross-polarization scattering from low-frequency electromagnetic waves in the GAMMA10 tandem mirror

A cross-polarization scattering (CPS) diagnostic method was applied to the GAMMA10 tandem mirror in order to study electromagnetic plasma waves with f requency less than 10 MHz. In the CPS process, an incident ordinary (extrao rdinary) wave is converted to an extraordinary (ordinary) wave by magnetic fluctuations in a plasma. The frequency spectra, and the density and magnet ic fluctuations of the waves can be evaluated from both the CPS and reflect ometry. The converted wave propagates through the cutoff layer and reaches a different diagnostic port with a receiver horn. The observed waves are id entified as the electromagnetic drift wave assuming the wave number matchin g condition. The low frequency waves nonlinearly coupled with the Alfven io n cyclotron waves are also observed with increase in the plasma pressure. ( C) 1999 American Institute of Physics. [S0034-6748(99)67501-3].