Alcator C-Mod Weekly Highlights July 12, 2004 FY 2004 weeks of operation planned: 18 weeks, completed: 18.9 weeks. We are currently up-to-air with the primary goal of installing the lower hybrid launcher. In addition, a large number of invessel activities are ongoing in support of ICRF and diagnostic systems. Maintenance and upgrades to diagnostic and power systems are also in progress. Physics ------- Three papers detailing instrumentation of and results from the ECE and neutral beam systems on C-Mod have been accepted for publication: "The Electron Cyclotron Emission (ECE) as a Density Fluctuation Diagnostic," by Perry Phillips, A. G. Lynn, A. Hubbard was accepted for publication in the Review of Scientific Instruments. "Upper limit on turbulent electron temperature fluctuations in the core of Alcator C-Mod," by C. Watts, P. Phillips, A. Hubbard, Y. Kin, and R. Gandy was accepted for publication in Nuclear Fusion. "Interpretation of Neutral Beam Emission Spectra as the Beam-Component Density Distribution," by William L. Rowan and M. B. Sampsell, and R. S. Granetz was accepted for publication in the Review of Scientific Instruments. Operations ---------- We continued to clean, refurbish, and reinstall first wall molybdenum tiles last week. Invessel work also continued on the MSE calibration. Both the D- and E-Port antennas have been reinstalled invessel with molybdenum tiles now replacing all boron nitride tiles. Work continues on the fabrication of new molybdenum tiles for the J-Port antenna. Installation of the 8th non-axisymmetric field coil below the B-Port horizontal port has been completed. Lower Hybrid Engineering ------------------------ Forty-seven out of forty-eight rwg/fwg assembly waveguides have successfully passed our 100 kW/0.5 s high power test. One waveguide is currently limited to lower power and requires additional investigation. A 3-window prototype has been prepared with a thinned outer wall that we expect to reduce stresses on the alumina windows experienced during brazing. We should have results from this test early this week. 144 metalized alumina windows arrived last week and are undergoing inspection at MIT before they are sent out for plating later this week. Assuming they pass our testing procedures, these windows will be used for the production of five lower hybrid coupler modules (four required for the launcher plus one spare). Work continued last week on the amplitude and phase control system. Calibrations and the development of look-up correction tables to remove non-linear behavior for all twelve channels is underway. Diagnostics ----------- Two Color Interferometer (TCI): Work continued on a set of buffer amplifiers that will allow better monitoring of TCI signal levels. We also continued to work on the installation of new cables to reduce crosstalk between TCI channels. The TCI CO2 laser and cooling unit were removed from the cell in preparation for the new CO2 laser. Many TCI optical components have been removed and cleaned. Active MHD Antennas: We continue to debug and make operational new amplifiers to drive the MHD antennas. Travel and Visits ----------------- Yijun Lin attended two workshops in China: the 2nd US-China Fusion workshop, June 23-25, Kunming, and the 3rd Chinese Academy of Sciences Plasma Physics Workshop, July 3-6, Hefei, China. He presented recent ICRF results from C-Mod on both workshops. He also visited ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) and discussed collaboration opportunities.