Benchmar king of electr on heat diffusion models in TJ -II plasmas

Abstr act PRETOR-Stellarator predictive transport code has been used to simulate transport phenomena in TJ-II. Some new electron heat diffusivity models have been introduced in the code in order to compare their results with the experimental ones in TJ-II and, hence, to elucidate their validity to explain TJ-II transport properties. Two types of discharges have been considered to perform the benchmarking of these models, the first one corresponding to a standard shot and the other one to enhanced heat confinement regime. Results show that semi local ee-scaling developed to explain W7-AS results show a good agreement with the experimental data. Regarding the drift-wave based model, we have to say that, although the included models were developed to simulate tokamak shots, a reasonable agreement with experimental data is obtained. Intr oduction We have developed the PRETOR-Stellarator transport code 1 . PRETOR code, that was developed initially to simulate tokamak shots, was completed in the “Departament de Fisica i Enginyeria Nuclear” of “Universitat Politecnica de Catalunya” DFEN with a new module capable to simulate stellarator shots. PRETOR-Stellarator is being used to simulate TJ-II shots. TJ-II 2 is a medium size four periods stellarator, of flexible heliac type, with magnetic field Bt0o1.2T, major radius R0=1.5 m, average minor radius o 0.2 m, that can achieve a wide range of rotational transform values at the center: 0.9o k*2+/2ro2.2. Usually the LHD pseudo-experimental model 3 is used in transport study of TJ-II. In this paper new models are added in order to check the goodness of each one and make a comparison among them. The results could be interesting in order to improve the transport calculations in TJ-II or confirm the validity of the usual model used. Also the implementation of the theoretical transport models would help to enlarge the validity of these theories developed for tokamaks plasmas that have not been used in TJ-II plasmas.