Alcator C-Mod Weekly Highlights November 20, 2006 FY2007 weeks of research operations: tentative target: 15 weeks Completed: 0 weeks Operations ---------- In-vessel work continued last week with installation of more 3/8" studs on the upper EF1 heat shield needed to support the new cryopump. A 20% section of the cryopump protection hardware was successfully installed including the shim and ceiling plates, and support posts. Clearances were measured and found to be as designed. Installation of TZM (molybdenum alloy) tiles on the the ceiling plates has begun. Long Pulse Diagnostic Neutral Beam ---------------------------------- Modifications to the DNB support stand in the cell were completed with the addition of the top deck support for the HV transformer. Machining of the F-Port flange components is also complete and fit-up and welding will start as soon as fixturing blocks needed to maintain alignment are fabricated. Lower Hybrid System ------------------- Following re-commissioning of the HVPS, work began last week on optimization of the lower hybrid system power capability. By Friday, up to 3.15 MW of total source power was available from twelve klystrons into dummy loads with 10 ms pulses. The klystron test stand work continued with pulsed HV system component values being optimized. Work continued on the klystron refurbishment program. Coupons of kovar plate were water jet cut this week and final machining done in preparation for plating and brazing tests. Kovar will be used in the fabrication of new cathode assemblies. A 24-window coupler braze test indicates stresses are reduced on the edge vacuum windows below allowables for alumina if a double flange design is used. Earlier designs showed crack growth in the outer most windows. This result is consistent with FEA analysis. Diagnostics ----------- Bill Rowan and Igor Bespamyatnov, both of U. Texas, have been working to upgrade the spectrometer used for high resolution measurement of MSE spectra to improve data acquisition and throughput. At the beginning of the next campaign, the spectrometer will be used to help assess the effects of the 7 degree toroidal rotation of the DNB on the balmer-alpha spectra used for MSE. This week, the data acquisition system for the spectrometer was redesigned including important input from David Terry. The data acquisition will be upgraded from CAMAC based to PCI-based for the upcoming campaign. Ron Bravenec, U. Texas, discussed QCM radial phase measurements with Jim Terry, specifically to explore what BES data may already have been taken and what data could be obtained during the next run campaign. ICRF Systems ------------ We continued inspections of the D-Port ICRF antenna last week. Re-assembly of the E-Port antenna continued. The design of the control system for the FFT is proceeding and has progressed to the point that interconnecting cabling can be specified. Design of the FFT mounts and placement of the tuners and rack cabinets in the cell have begun as has planning of the routing of the transmission line coax. Travel and Visits ----------------- Professor Yuan-Xi Wan, former director of the Chinese Academy of Science Institute of Plasma Physics (ASIPP), located in Hefei, and current head of the EAST superconducting tokamak project, visited MIT on Monday and Tuesday of this week. In addition to presenting a PSFC seminar on EAST results and plans, he met with many C-Mod scientists and students to discuss topics of mutual interest, including possible areas of enhanced collaboration between the C-Mod and EAST teams. Approximately thirty representatives of the Total Corporation (France) visited the PSFC on Tuesday afternoon. As part of their visit, Earl Marmar gave them a brief introduction to C-Mod, and they toured the experimental facilities. David Mikkelsen spent the week at MIT analyzing data from MP428 and discussing possible future experiments. The electron temperature gradient scale length can be derived from Te profiles measured by the FRC-ECE system, but sawteeth generate 'noise' that is significant in the region of most interest. Methods of dealing with this noise were developed this week. Perry Phillips, U. Texas, visited MIT last week. He met with Dave Mikkelsen, PPPL, to review ECE profiles in ITB discharges, Brian Labombard to seek probe measurements to support investigation of non-thermal EC emission in the SOL, and Arturo Dominguez to confirm what reflectometer measurements will be available during the next campaign for comparison with FRCECE. A detailed discussion with J. Terry centered on comparisons of FRCECE and GPI QC-mode fluctuation measurements and on collaborations during the coming campaign. These will include continued comparisons of fluctuation results and investigation of ELM'ing discharges. Catherine Fiore hosted the visit of Jim Strachan, PPPL, last Friday. He also met with Earl Marmar, Joe Snipes, Bob Granetz, Bruce Lipschultz, Brian Labombard, and Dennis Whyte while he was at MIT, and gave the PSFC seminar on "Carbon Migration Studies in JET." _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly