Alcator C-Mod Weekly Highlights November 26th, 2007 FY2008 weeks of research operations: Target: TBD Completed: 0 weeks Physics ------- Jim Terry became a Fellow of the APS during the 49th Meeting of the DPP APS. Jim has made major contributions to the physics programs of Alcator C, C-Mod, and TFTR. His citation reads "For significant contributions in the areas of volume recombination in plasmas, plasma impurity transport, wall-conditioning with lithium, plasma transport, and plasma turbulence in magnetic fusion confinement devices." Operations ---------- On Tuesday of last week power supply tests were begun for the FY2008 campaign. All tests were completed successfully by mid-afternoon and two attempts were made for plasma. Both attempts produced breakdown indicating that the new flux loops are working, as well as the Digital Plasma Control and Gas Puff systems. Numerous diagnostics are also back on-line. However, a vacuum leak that developed during the bake cycle was large enough to stop the current rise. Both Wednesday and Friday were devoted to finding the leak, which was eventually found in a re-entrant tube on one of the lower vertical ports. On Saturday, we backfilled with nitrogen, removed the tube, and blanked off the flange. A low temperture bake and ECDC have produced good vacuum conditions, and C-Mod is ready for plasma operation. Lower Hybrid System ------------------- We continued modeling efforts on the 4-way splitter that will be used in the 2nd lower hybrid launcher. Considerable progress has been made in reducing the electric fields in the splitter, and they are now approaching what would be expected of a standard waveguide. Construction has begun on the 4th lower hybrid cart stand. The stand will support four klystrons and sockets and much of the klystron instrumentation. Work is also well underway on the cart electronics. Circulators for the new cart are expected to be delivered by the end of the year. ICRF Systems ------------ Work continued on re-installation of the Fast Ferrite Tuner (FFT) for the E-Port antenna. Changes have been made to the tuner intended to increase its high voltage operation capabilities. Initial operation of the FFT during the last campaign was very encouraging. We also continued work on an acoustic arc detector to be used to locate and protect against arcs at high rf voltage locations in the rf transmission lines. DNB --- A new shutter/aperture system for the DNB is being prepared for installation. This new aperture, located in the beamline, will improve the spatial resolution of DNB diagnostics such as MSE and CXRS when a second aperture is installed in-vessel during the next up-to-air period. Travel and Visits ----------------- Bruce Lipschultz attended the 5 year review of the Physics of Plasmas at PPPL on November 20. He was part of a committee that reviewed the operation and goals of the journal over the past 5 years. Costanza Zucca, CRPP-Lausanne, visited C-Mod last Friday and was hosted by Joe Snipes. Dr. Paolo Scarin from RFX (the Reversed Field eXperiment) in Padua, Italy, visited the PSFC on Nov. 19 and 20 and discussed GPI (Gas Puff Imaging) results. He gave a presentation on "Analysis of intermittent structures on RFX-mod GPI data and comparison with other toroidal devices " to the C-Mod group. His analysis included data from C-Mod. He also discussed with J. Terry and I. Cziegler the interpretation of the present results, as well as the continued collaboration between RFX and C-Mod scientists on the analysis of C-Mod's GPI data. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly