Far-forward scattering observations of an Alfven wave experiment

Abstract

Par-foward scattering of submillimetre laser radiation has been used to deten Ihe density fluctuations associated with the discrete ALfven wave and kinetic Alfvh wave resonances in an Alfvdn wave experiment on the TORTUS tokamak. With the aid of calculations, in which interaction of the radiation with he waves is desaibed in terms of diffraction by a phase grating representation of the plasma density fluctuations, it has been possible to distinguish unambiguously between the two resonance conditions. This was not possible, in the present experimenL using magnetic pmbe diagnostics alone.

Scattering from discrete Alfven waves in a tokamak using a gyrotron radiation source

“…Even though little or no heating has been observed, the appearance of the global discrete AlfvCn wave (DAW) resonances and the transition to KAWs during the lifetime of the plasma can be studied. Recently, Bowden and James (1992) have reported scattering from DAW resonances and KAWs using a 433pm optically pumped formic acid vapour laser as the radiation source. They successfully distinguished between the DAW resonances and the KAWs.…”