Fusion Science and Technology / Volume 55 / Number 1 / January 2009 / Pages 76-83
Technical Paper / Electron Cyclotron Emission and Electron Cyclotron Resonance Heating
The codes SNECTR, CYTRAN, CYNEQ, and EXACTEC 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 reabsorption in the edge plasma. The assumption of isotropy of the radiation intensity in the plasma that is adopted in both CYTRAN and CYNEQ (which cannot be justified a priori) is discussed and found to be adequate for strong diffuse reflection. However, it overestimates the net EC power loss in the plasma core for weakly as well as for specularly reflecting walls by up to 20%. 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 while for strong diffuse reflection EXACTEC is found to underestimate the net EC power loss typically by 20%. EXACTEC, CYTRAN, and CYNEQ are confirmed to be well suited for use in systematic transport simulations of fusion plasmas.