(IT/P18) EC Radiation Transport in Fusion ReactorGrade Tokamaks: Parameterization of Power Loss Density Profile, NonThermal Profile Effects under ECCD/ECRH conditions
A.B. Kukushkin^{1)},
K. V. Cherepanov^{1)},
L. K. Kuznetsova^{1)},
E. Westerhof^{2)}
^{1)} RRC "Kurchatov Institute", Moscow, Russian Federation
^{2)} FOMInstitute for Plasma Physics Rijnhuizen, Association EURATOMFOM, 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 steadystate scenarios of ITER operation. Strong sensitivity of the net ECR power loss density profile,
P_{EC}(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/P656] for ITER scenario 2 (Inductive). Here we report on solving the following three tasks for ITERlike conditions: (1) approximate analytic description of the profile
P_{EC}(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/P656] 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., Omode n=1), using the beam tracing code TORBEAM [Poli E., et al., Comp. Phys. Commun., 2001, 136, 90] and the FokkerPlanck code RELAX [Westerhof E., et al., Rijnhuizen Report RR 92211 (1992)]; (3) modeling, with the code CYNEQ, of the profile
P_{EC}(r) for the nonmaxwellian EDF of item 2 to evaluate the influence of ECCD/ECRHproduced superthermal electrons on the profile
P_{EC}(r), which, for the ITER case, is dominated by the transport of plasma’s ECR at harmonics n∼310. The combined calculations with the codes TORBEAM+RELAX+CYNEQ for scenario 2 predict maximal impact of the ECCDproduced superthermal electrons on the profile
P_{EC}(r) (a∼20% rise in the core) for oblique launch with full power deposition in the center (e.g., for equatorial launch at 170 GHz, Omode, n = 1,
with toroidal injection angle
β∼20^{o}).
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