Integrated Plasma Simulation of Sawtooth Modification via Lower Hybrid Current Drive in Tokamaks*

An advanced lower hybrid RF (LHRF) actuator component was been implemented in the Integrated Plasma Simulator [1], and has been used to simulate modification of sawteeth via lower hybrid current drive (LHCD). The TSC transport code [2] is used to evolve the background plasma in conjunction with the Porcelli sawtooth model [3], and driven LH current density profiles are computed using the GENRAY ray tracing code which includes a scrape off layer and the CQL3D Fokker Planck code [4]. The integrated model has been tested against a series of experiments [5] in the Alcator C-Mod tokamak in which sawteeth were systematically delayed for increasingly longer periods of time as the level of LHCD was increased.\\[4pt] [1] D. Batchelor \textit{et al}, Journal of Physics: Conf. Series \textbf{125}, 012039 (2008).\\[0pt] [2] S. C. Jardin \textit{et al}, J. Comp. Phys. \textbf{66}, 481 (1986).\\[0pt] [3] F. Porcelli, Plasma Phys. Cont. Fusion 38 (1996) 2163.\\[0pt] [4] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Meeting on Simulation and Modeling of Therm. Plasmas, Montreal, Canada (1992).\\[0pt] [5] C. E. Kessel \textit{et al}, Bull. Am. Phys. Soc. \textbf{53}, Poster PP6.00074 (2008).