BENCHMARKING OF CODES FOR CALCULATING LOCAL NET EC POWER LOSSES IN FUSION PLASMAS

The SNECTR, CYTRAN, CYNEQ and EXACTEC codes are compared in view of the calculation of the profile of the net electron cyclotron (EC) wave power density emitted for different electron temperature profiles and average temperatures of relevance for reactor-grade magnetoplasmas. The effects of either specularly or diffusely reflecting walls are assessed for a cylindrical plasma with circular cross-section, specular reflection, as assumed in EXACTEC, providing a lower bound to the net EC wave power losses in the hot plasma core (and therefore, as a rule, also to the total EC power loss) as well as to re-absorption in the edge plasma. The assumption of isotropy of the radiation intensity in the plasma underlying both CYTRAN and CYNEQ, is discussed and found to be adequate for strong diffuse reflection, however overestimating the net EC loss in the plasma core for weakly reflecting walls by up to 20%. On the whole, the full transport code SNECTR (no longer in active use), for specular reflection, and the exact cylindrical code EXACTEC are in excellent agreement with each other, CYTRAN and CYNEQ resulting to be fast routines suited for use in systematic transport simulations of fusion plasmas.