RAYTEC: a new code for electron cyclotron radiative transport modelling of fusion plasmas

As it was recognized that local electron cyclotron (EC) wave power losses can be a competitive contribution to the 1D electron power balance for reactor-grade tokamak plasmas in regimes as anticipated for steady-state operation, a systematic effort is ongoing to improve the modelling capability for the radial profile of EC wave emission. This effort aims at generating a hierarchy of codes that cover the non-local behaviour of EC wave transport for inhomogeneous plasmas and in the presence of reflecting walls with increasingly improved accuracy and also provide sufficient computational efficiency for being usable in 1D transport studies. The recently developed code RAYTEC, which explicitly addresses the geometrical effects present in toroidal plasmas with arbitrary cross-section, is described and used to investigate the impact of elongation of the plasma cross-section and of toroidicity on the angular dependence of the EC radiation field, on the profile of the net EC wave power density lost from the plasma and on the total EC power loss for ITER-like plasma conditions. Furthermore, a comparison is made with the results of simpler models in use to describe both local and total EC power losses as well as with ones obtained from analytical formulae that are introduced on the basis of Trubnikov's formula for EC power emission.