Alcator C-Mod Weekly Highlights October 3, 2005 FY2006 weeks of research operations Planned: TBD Completed: 0 weeks Operations ---------- We continued work in-vessel last week. Installation of the J-Port antenna septa, tests of MSE optics, and alignment checks of other optical diagnostics were completed. Outer divertor cover plates that had been removed for cleaning and analysis of surface coatings were reinstalled. Over the weekend a final wipe-down of the vessel walls was completed, survey documentation made, and installation of horizontal flanges was begun. Pump-down is planned for early this week. Physics Research ---------------- Initial results from the new NeSoXs soft X-Ray spectrometer suggest that there are strong poloidal flows in the edge regions of Alcator C-mod plasmas. The flows are of the same order predicted by neo-classical theory (10s of km/s), with H-mode plasma having larger flows than L-mode plasmas. ICRF Systems ------------ Repairs to the FMIT#3 power supply diode stack have been completed. Re-installation of the stack is scheduled for later this week. We successfully completed installation of the new J-Port antenna septa which replace the Faraday screen. A picture of the J-Port antenna with the new septa can be found at http://www.psfc.mit.edu/cmod/operations/EngImages/INVESSEL/2005/20051003_close_up_survey/DSCN0744a.JPG Lower Hybrid System ------------------- Bob Childs worked with the vendor last week to plate the 24-window prototype and the #2, #3, and #4 couplers. Eddy current and X-Ray analysis indicates the plating is of high quality. These components are now being baked and undergoing braze tests. Machining of the replacement #1 coupler is expected to be complete by the end of this week. Diagnostics ----------- A series of calibrations of the Motional Stark Effect (MSE) diagnostic have been carried out during the up-to-air period. A comprehensive dataset was acquired to study various issues affecting the MSE system: angle-of-incidence effects on the in-vessel wire grid polarizer; effects of light scattering in the MSE optical train; effects of variations of retardance across the surface of the photoelastic modulators; effects of electronic gain; and changes in the absolute calibration due to deterioration of electronic components. These data are being analyzed. Travel and Visits ----------------- Dr. Songtao Wu, a deputy director of the Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) is visiting for several days and talking with C-Mod engineers and physicists about both C-Mod and the new EAST tokamak. Dave Terry, William Burke, Dexter Beals, and Peter Koert presented posters at the Symposium on Fusion Engineering (SOFE) 2005 meeting in Knoxville on aspects of the lower hybrid system, the long pulse DNB, and real-time control of the Active MHD Antenna Diagnostic. Peter Titus, Fusion Technology and Engineering Division of PSFC, presented a poster on the design of the new upper divertor cryopump. Bob Granetz presented an invited talk on "Alcator C-Mod Status, Recent Accomplishments, and Future Plans." Ian Hutchinson attended the Plasma Science Committee of the Board on Physics and Astronomy of the National Academies (23-26 Sep), which discussed issues concerning the health of the plasma physics disciplines and notably the plans for the Plasma 2010 decadal survey. Amanda Hubbard and Ted Biewer attended the 10th IAEA TCM on H-modes and Transport Barriers in St. Petersburg, Russia. Amanda presented a poster on "Comparisons of small ELM H-Mode regimes on the Alcator C-Mod and JFT-2M tokamaks." Ted presented a poster on "Extension to pedestal scaling studies on the Alcator C-Mod Tokamak." Alex Klein, Columbia University, visited on 27 September and presented a talk on "High-speed Digital Mode Control Feedback on External Kink Modes in the HBT-EP Tokamak." _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly