Alcator C-Mod Weekly Highlights June 13, 2011 FY2011 weeks of research operations Target: 15 weeks Completed: 14.5 weeks Plasma Shots: 1706 Mid-Term Review --------------- On Monday, C-Mod made its presentations to the DoE FES Midterm Review, which is a peer panel review of the three major fusion facilities (C-Mod, DIII-D and NSTX) at about the halfway point of the current 5 year grant period. Earl Marmar, Bruce Lipschultz and Martin Greenwald traveled to DoE Germantown for the review, and other members of the C-Mod team participated by video-conference from MIT, PPPL and U. Texas. Physics ------- "Full wave effects on the lower hybrid wave spectrum and driven current profile in tokamak plasmas", by S. Shiraiwa et al., has been accepted for publication in Physics of Plasmas. "Lower hybrid current drive at high density in Alcator C-Mod", by G. Wallace et al,, has been accepted for publication in an upcoming issue of Nuclear Fusion. This paper is based on work presented at the IAEA Fusion Energy Conference in Dajeon, Korea in October 2010. Paul Bonoli is beginning a collaboration with Professor Sadayoshi Murakami, Kyoto University, that will use Professor Murakami's GNET Monte Carlo orbit code to study the ICRF induced rotation that is observed in Alcator C-Mod. This code solves the drift kinetic equation and is coupled to an RF "kick" operator that employs analytic expression for the left circularly polarized ICRF electric field. Operations ---------- In-vessel work last week included ultrasonic cleaning of the D- and E-Port antenna protection tiles, and the use of de-ionized water to clean the remaining antenna components. Inner wall modules were reinstalled in parallel with the new gas puff capillary. First wall instrumentation at J-Port has been updated with fast response thermocouples. Routine maintenance on the alternator moved from alternator to flywheel pressure switches last week. Work on the alternator and flywheel emergency DC lube oil pump motor starters has been completed. ICRF Systems ------------ A trial assembly of the ARRA funded rotated antenna on the test stand has been completed: http://www.psfc.mit.edu/research/alcator/facility/rot_ant_assembly.jpg The outer two straps and their associated strip line leads will be sent out to be plated in the coming week. The first bellows tube has been plated and is being baked in our vacuum oven to test plating adhesion. Based on initial visual inspections, the quality of the plating appears to be excellent; this will need to be confirmed by the bake and subsequent peel tests. We are cutting to length and threading test Faraday screen rods to qualify the process before proceeding with the actual rods. We have polished enough resistive washers to make one full Faraday screen assembly. Lower Hybrid System ------------------- Work continued on the design of the LH FFT system. Analysis is under way to determine the effect of moving the ferrite off the center (high E-field region) and toward the sides (low E-field region) as is done in the design of some circulators. Cabling is being fabricated and time delay relays have been installed and tested in the collector over-temperature panels for the Transmitter Protection System. Travel and Visitors ------------------- Peter Welch, U.S. Congressman from Vermont, visited the PSFC on Tuesday 6/7 for a tour of the Alcator C-Mod facility. Representative Welch has a strong interest in clean energy technologies. Amanda Hubbard attended the Chalmers workshop on nonlinear phenomena in fusion plasmas (CNR), held in Varenna, Italy. She gave an invited talk entitled "Transitions to H-mode and I-mode Edge Transport Barriers on Alcator C-Mod". Paul Bonoli hosted the visit of Sadayoshi Murakami on Monday - Wednesday (June 6-8, 2011). Professor Murakami is a computational physicist from the Nuclear Engineering Department at Kyoto University. He gave a talk at the Turbulence User Group Meeting on Tuesday, June 7, on "Simulation study of toroidal flow generation by ICRF minority heating". During his visit he met with several of the Alcator staff scientists and graduate students including Professors Parker and Hutchinson, Matt Reinke, Jungpyo Lee, John Rice, Syun'ichi Shiraiwa, and Catherine Fiore. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly