Alcator C-Mod Weekly Highlights April 19, 2010 FY2010 weeks of research operations Base Target: 13 weeks Base Completed: 9.7 weeks ARRA Target: 5 weeks ARRA Completed: 5.0 weeks Plasma Shots: 1630 TTF Meeting ----------- Eleven C-Mod related presentations were given at the TTF meeting in Annapolis, MD, April 12-16. Representing C-Mod were Martin Greenwald, Amanda Hubbard, John Rice, Jerry Hughes, Catherine Fiore, Nathan Howard, Arturo Dominguez, Istvan Cziegler, Yunxing Ma, and Igor Bespamyatnov (U-Tex). Presentations from C-Mod personnel will be made available soon at http://www.psfc.mit.edu/research/alcator/pubs/TTF/TTF_2010_abstracts.htm Jerry Hughes attended the Edge Coordinating Committee meeting on April 12 to report on C-Mod's status and plans with respect to the FY11 Joint Research Milestone. Research opportunities associated with this milestone were discussed extensively throughout the week by the personnel involved. While at the meeting, Martin Greenwald met with members of the NSTX and DIII-D teams to discuss a FY12 joint research target on core transport. There was general agreement that such a milestone would stress comparisons between codes and experimentally measured profiles, fluxes and fluctuations. Later discussions with Curt Bolton suggest that the 2012 facilities target will not be combined with the theory milestone as was done for FY11. Martin also gave a talk to the Verification and Validation Working Group. Operations ---------- In-vessel work continued last week. All outer divertor modules have been removed from the machine. High heat load areas that experienced erosion are being documented, and plans are being developed to reduce the heat load to these areas. Analysis of the boron coated tiles indicates that there is little net erosion on the outer divertor tiles (79-82 um). However, de-lamination of the coating on some tiles is being investigated. Preparations for in-vessel calibrations of several diagnostics are being made, and post run calibrations of the Surface Science Station and Wall Bolometer diagnostics were completed last week. Work has begun on the MIT funded upgrade to the Alternator water cooling system. Supports for the new piping are being installed, and conduit for the electrical services is being run. Concrete pads for the pumps and heat exchangers have been poured. Lower Hybrid System -------------------- Phase and amplitude measurements of the lower hybrid launcher and jungle gym have been completed. These data have been used to specify shim-plate phase-shifter dimensions that match the column-to-column phases of the array. The plates are now being machined to the proper length. The first of seven new klystrons has successfully passed initial high power testing at our vendor's facility. Travel plans are being made for one of our engineers to witness acceptance tests of the first three tubes. Code has been developed to make the new rf probe calibration procedure part of the standard lower hybrid system. The code has been tested and phase and amplitude corrections verified. ICRF Systems ------------ We have characterized the new 4-strap antenna vacuum feed-through and adapters with a network analyzer. The VSWR is acceptably low for high power testing of the feed-throughs to begin. An rf breakdown experiment is being fabricated to investigate the influence of materials on the rf breakdown limit of ICRF antennas. A ridge waveguide is used to reduce the cavity dimensions at 80 MHz to a manageable dimension (16"x40"). An rf power of 100 kW will result in electric fields of up to 20 kV/cm. Experiments planned include copper, molybdenum, stainless steel, and tungsten as test metals. Low power rf tests of the ridge waveguide indicate some modifications will be required to optimize the electric fields generated. Diagnostics ----------- The lower optical table enclosure for the C-Mod Polarimeter diagnostic was pressurized with dry air for the first time last week and control and monitoring instrumentation for this system is being tested. Fabrication of the PLC control system and the FIR detector amplifiers for the Polarimeter also continued last week. Luis Delgado-Aparicio, PPPL, has relocated to the Boston area and will work with John Rice, Matt Reinke, Yuri Podpaly, Manfred Bitter, PPPL, and Ken Hill, PPPL, on the Hirex-Sr diagnostic. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly