Alcator C-Mod Weekly Highlights July 28, 2008 FY2008 weeks of research operations: Target: 15 weeks Completed: 15.7 weeks Physics ------- Alcator C-Mod related contributions to the 50th DPP APS meeting will include: 7 invited oral (experiment and theory/modeling) 12 contributed oral (C-Mod session) 2 contributed oral (ITER session) 27 contributed poster (C-Mod session) In addition, Martin Greenwald is slated to give an invited tutorial presentation entitled "Verification and Validation for Magnetic Fusion: Moving Toward Predictive Capability". Robert Granetz has compared experimental results from other tokamaks as presented at an ITER workshop on disruption-generated runaway electrons. Experiments in Alcator C-Mod have shown that even when there is a large population of suprathermal or relativistic electrons prior to a disruption, they are all lost at the thermal quench of a disruption, leaving no seed to start an avalanche process in the current quench. However, numerous other tokamaks presented data showing frequent occurrences of large runaway populations during the current quench, including TEXTOR, Tore-Supra, FTU, JT60-U, and JET, particularly in its early days when it was a limited machine. It was noted that many of these machines run circular, limiter discharges, and that all of them run at elongations much less than C-Mod. This result suggests C-Mod should run disruption experiments on low elongation discharges to see if an avalanche can be generated during the disruption current quench. Operations ---------- All TF arms and legs have been removed and are being evaluated and documented. The lower wedge plate has been lowered away from the vessel and the plates that enclose the PF coils can now be removed. All three OH coaxes have been removed and were found to be in excellent condition with the feltmetal still in like-new condition. Preparations are being made to remove the TF core and OH stack. We continue to prepare for the alternator inspection. Lifting fixtures needed for the inspection are being cleaned and prepared for use. The removal of instrumentation wiring and sensors continued. ICRF Systems ------------ Work continued on the new IPA system for the FMIT transmitters. A design review of the new 4-strap antenna will take place on July 30. Lower Hybrid System ------------------- The 4-way splitter prototype is complete and preparations are being made for low and high power tests. Two techniques for producing the 64 vacuum windows for the new launcher have been successfully prototyped. One technique brazes the windows in the middle copper section of a compression brazed stainless steel, copper, stainless steel waveguide laminate in which the waveguide has been electric discharge machined. The other technique electro-forms the window in place between two waveguide sections. More prototype work is required before a decision is made on which technique to use in the production launcher. Travel and Visitors ------------------- Last week, Ron Parker attended the 3rd meeting of the European Fusion Facilities Review Panel in Brussels. The panel's charge is to review the R&D and facilities needed to realize fusion energy in a European demonstration fusion reactor in a time frame of 30 - 35 years. The panel's report, due in October, will provide important input to the European Commission in a planning process leading to a coherent program of European research over the next decade and beyond in support of ITER and the follow on step of a DEMO reactor. Ed Synakowski, LLNL, visited the PSFC for discussions with Paul Bonoli, Martin Greenwald and Amanda Hubbard. Topics included ITER research plans and the proposed Fusion Simulation Project. Earl Marmar traveled to the Washington D.C. area last week. On Wednesday morning he gave a presentation to the Office of Fusion Energy Sciences in Germantown, MD, entitled "Alcator C-Mod Highlights and Plans", and had additional discussions with Ray Fonck and Rostom Dagazian. Ian Hutchinson and Earl Marmar attended the APS-DPP program committee sorters' meeting in College Park, MD, last week, where they participated in planning for the 2008 conference. Bruce Lipschultz attended the US Plasma Facing Components meeting in Albuquerque on July 22. He presented a review of C-Mod research and plans in this area. In addition, he presented a review of ITPA efforts on SOL physics and plasma-surface interaction. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly