Alcator C-Mod Weekly Highlights November 19, 2012 FY2013 weeks of research operations Target: tbd Completed: 0.53 weeks Plasma Shots: 61 Operations ---------- We have completed a series of experiments using the new RFQ accelerator (AGNOSTIC) and associated diagnostics for in-situ studies of C-Mod plasma facing components. LN2 cooling to the magnets has been stopped, and C-Mod is warming up to room temperature. Glow discharge cleaning is on-going to remove diborane products and prepare the vessel for personnel entry. ICRF Systems ------------ Repairs are being made to the FMIT#4 phase shifter. Arc damage has been localized to one of the push/pull rods. Inspections of the new FFT units continue. Lower Hybrid System ------------------- High power testing of the LH3 3dB bijunction splitter assembly was successfully completed. The bijunction was able to withstand the maximum klystron output (over 230 kW of forward power) for 0.5 s after a brief conditioning period. In normal operation, each bijunction will be subject to 25% of the forward power from each klystron, or ~50 kW. Previous testing at low power showed nearly ideal splitting performance and low losses. Faulty collector coolant thermocouples were replaced on klystrons 3 and 11. A loose connection on the klystron 11 coolant pressure gauge was also fixed. All klystrons were run for 3.0 s pulses at 40 kV and 80 kW to collect data on the collector heat capacity for each klystron. Diagnostics ----------- AGNOSTIC carried out a week long set of experiments to measure the changes in PFC surface composition on the inner wall of C-Mod due to boronization, ECDC, and glow discharge cleaning (GDC). The RFQ accelerator and accompanying 3 particle detectors that form the core of AGNOSTIC performed very well during the measurements. Deuteron-induced neutron and gamma spectra were recorded at 4 poloidal locations along the inner wall. A boronization was carried out with the resonance layer held as close to the inner wall PFCs as possible to maximize the effect on the PFCs. Following a 24 hour GDC, final measurements were taken on Friday to assess the inner wall PFC composition prior to beginning preparations for venting of the vessel. Remote Participation, Travel, and Visitors ------------------------------------------ Following the APS-DPP meeting, Professor Bo Li (Peking University, Beijing) visited the PSFC for a two week period to discuss results from his new 3D pedestal/scrape-off-layer fluid turbulence code, and to continue his SciDAC collaboration with Darin Ernst. Li also presented a special PSFC seminar on November 6 entitled "Flux-driven 3D global fluid simulations of plasma edge turbulence." Professor Barrett Rogers (Dartmouth University) also visited on November 6 to discuss collaborations on edge and core turbulence. Li, Ernst, and Rogers met with Brian LaBombard, Jim Terry, Bruce Lipschultz, and Martin Greenwald to discuss potential applications of 3D fluid simulations to C-Mod experiments. Steve Wolfe served as chairman of the Conceptual Design Review for the ITER Plasma Control System (PBS-47). The CDR was held in Cadarache, France, from 13-15 November; members of the panel remained in Cadarache on 16 November to work on the Final Report of the Review. Don Batchelor and Wael Elwsaf, Oak Ridge National Laboratory, visited Paul Bonoli and John Wright on Wednesday-Friday (November 14-16, 2012). They worked together on building the Integrated Plasma Simulator (IPS) on the PSFC Loki Computing Cluster, and they also worked on modifications to the TORIC ICRF component of the IPS that will allow time dependent 3-D (multiple toroidal mode) simulations of ICRF heating. Don and Wael also had discussions with Martin Greenwald and John Wright on issues related to data archiving for numerical simulations, and they met with Darin Ernst to discuss the IPS framework. David Brower and Weixing Ding, UCLA, visited MIT last week to discuss plans for the C-Mod Polarimeter collaboration. Yinxian Jie and Haiqing Liu, EAST tokamak, Hefei, China, who are collaborating with UCLA, also visited for discussions on polarimetry and to see the C-Mod Polarimeter and Two-Color-Interferometer systems. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly