Effect of density fluctuations on ECCD in ITER and TCV
1 CEA, IRFM, F-13108, Saint-Paul-lez-Durance, France
2 EPFL, CRPP, Association EURATOM – Confédération Suisse, CH – 1015 Lausanne, Switzerland
a e-mail: email@example.com
Density fluctuations near the edge of tokamak plasmas can affect the propagation of electron cyclotron (EC) waves. In the present paper, the EC wave propagation in a fluctuating equilibrium is determined using the ray-tracing code C3PO. The evolution of the electron distribution function is calculated self-consistently with the EC wave damping using the 3-D Fokker-Planck solver LUKE. The cumulative effect of fluctuations results in a significant broadening of the current profile combined with a fluctuating power deposition profile. This mechanism improves the simulation of fully non-inductive EC discharges in the TCV tokamaks. Predictive simulations for ITER show that density fluctuations could make the stabilization of NTMs in ITER more challenging.
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