Detection of disruption precursors and study of disruption phenomena by ECE and collective scattering diagnostics
In a systematic study on plasma disruptions at TEXTOR, MHD-modes and Marfes were detected as precursors to abrupt current terminations by ECE radiation. Different situations are presented where several MHD modes appear simultaneously and lead to a minor or major disruption. The precursor MHD oscillations are already visible in the collective scattering of a 150 GHz mm-wave. Highly enhanced density fluctuations are registered during mode locking and energy quench phases. A spectral study of the scattered radiation reveals characteristic properties of a turbulent plasma with high frequency density fluctuations. Prominent participants in the evolution to the turbulent state are the modes m/n = 2/1 and m/n = 1/1. A method is presented to identify these modes by a digital correlation technique in real time.
Bibliographic Reference: Article: Proceedings of Eighth Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, Vol. 1 (1993) pp. 237-249
Record Number: 199311129 / Last updated on: 1994-11-29
Original language: en
Available languages: en