(IT/P1-8) EC Radiation Transport in Fusion Reactor-Grade Tokamaks: Parameterization of Power Loss Density Profile, Non-Thermal Profile Effects under ECCD/ECRH conditions

A.B. Kukushkin1), K. V. Cherepanov1), L. K. Kuznetsova1), E. Westerhof2)
 
1) RRC "Kurchatov Institute", Moscow, Russian Federation
2) FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, The Netherlands

Abstract.  Electron cyclotron radiation (ECR) was shown [Albajar F., et. al., Nucl. Fusion, 45 (2005) 642] to contribute significantly to the local energy balance in the central part of the plasma column in steady-state scenarios of ITER operation. Strong sensitivity of the net ECR power loss density profile, PEC(r), to the presence of superthermal electrons was shown in [Cherepanov K.V., Kukushkin A.B., 20th IAEA Fusion Energy Conference. (Vilamoura, Portugal, 2004), TH/P6-56] for ITER scenario 2 (Inductive). Here we report on solving the following three tasks for ITER-like conditions: (1) approximate analytic description of the profile PEC(r) for maxwellian plasmas, tested vs. calculations with the code CYNEQ [Cherepanov K.V., Kukushkin A.B., 20th IAEA Fusion Energy Conference (Vilamoura, Portugal, 2004), TH/P6-56] and to be used as a simple simulator during the transport calculations, in particular, in the ITER case; (2) modeling of deviations of the electron velocity distribution function (EDF) from maxwellian, caused by the ECCD/ECRH at low harmonics of the cyclotron frequency (e.g., O-mode n=1), using the beam tracing code TORBEAM [Poli E., et al., Comp. Phys. Commun., 2001, 136, 90] and the Fokker-Planck code RELAX [Westerhof E., et al., Rijnhuizen Report RR 92-211 (1992)]; (3) modeling, with the code CYNEQ, of the profile PEC(r) for the non-maxwellian EDF of item 2 to evaluate the influence of ECCD/ECRH-produced superthermal electrons on the profile PEC(r), which, for the ITER case, is dominated by the transport of plasma’s ECR at harmonics n3-10. The combined calculations with the codes TORBEAM+RELAX+CYNEQ for scenario 2 predict maximal impact of the ECCD-produced superthermal electrons on the profile PEC(r) (a20% rise in the core) for oblique launch with full power deposition in the center (e.g., for equatorial launch at 170 GHz, O-mode, n = 1, with toroidal injection angle β∼20o).

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