Integrated Plasma Simulation of Lower Hybrid Current Drive Modification of Sawtooth in Alcator C-Mod

Experiments were performed in Alcator C-Mod, where the onset time for sawteeth was delayed significantly (up to 0.5 s) relative to ohmically heated plasmas, through injection of off-axis LH current drive power [1]. In this poster we discuss simulations of these experiments using the Integrated Plasma Simulator (IPS) [2], through which driven current density profiles and hard x-ray spectra are computed using a ray tracing code (GENRAY) and Fokker Planck code (CQL3D) [3], that are executed repeatedly in time. The background plasma is evolved in these simulations using the TSC transport code with the Porcelli sawtooth model [4]. \\[4pt] [1] C. E. Kessel \textit{et al}, Bull. of the Am. Phys. Soc. \textbf{53}, Poster PP6.00074 (2008). \\[0pt] [2] D. Batchelor \textit{et al}, Journal of Physics: Conf. Series \textbf{125}, 012039 (2008). \\[0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Mtg. on Sim. and Mod. of Therm. Plasmas, Montreal, Canada (1992). \\[0pt] [4] S. C. Jardin \textit{et al}, Journal Comp. Phys. \textbf{66}, 481 (1986).