PLASMA TURBULENCE DETECTED BY COLLECTIVE WAVE SCATTERING IN TEXTOR TOKAMAK

Collective millimetre wave scattering and electron cyclotron emission techniques were used to study precursor instabilities to forthcoming t okamak disruptions. A 150 GHz O-mode scattering diagnostic installed o n TEXTOR is briefly described. Tearing modes and MARFEs were observed prior to discharge disruption. Collective scattering spectra were eval uated from scattered radiation from different events and radial regime s on the tokamak plasma TEXTOR. The evolution of the scattering spectr a demonstrates the development of magnetohydrodynamic turbulence. This turbulence produces highly enhanced energy and particle fluxes and te rminates abruptly the confined plasma state. The disruptive evolution of a tokamak plasma is a big handicap for future fusion machines and e ither must be avoided or al least it must be reduced to a small number of events. (C) 1996 Published by Elsevier Science Ltd.