Non linear electron temperature oscillations on Tore Supra: Experimental observations and modelling by the CRONOS code

Full text: The recently discovered plasma regime characterised by stationary electron temperature oscillations (O-regime), has been the object of further experimental investigation and of extensive modelling by the integrated plasma simulation code CRONOS. The experiments include the observation of the O-regime in discharges at exactly zero loop voltage, oscillations trigger by ECCD and the study of the interplay of the O-regime with MHD activity. The possibility of feedback control of the amplitude and frequency of the oscillations using the LH power as an actuator has been investigated. Simulations with the CRONOS code have revealed the nature of the temperature oscillations, which are originated by a non-linear coupling of temperature and current density profiles, of the predator-prey type. It has been shown that oscillating solutions of the coupled heat and current diffusion equations are possible only for a selected class of heat transport models. Therefore, this regime represents a sharp test for transport theories and for integrated plasma simulation codes. (author)