Alcator C-Mod Weekly Highlights October 15, 2012 FY2013 weeks of research operations Target: tbd Completed: 0.53 weeks Plasma Shots: 61 Operations ---------- Planned maintenance of engineering systems began last week including work on the magnet power supplies, ICRF transmitters, and the alternator. No high power systems will be available for the next two weeks as scheduled work on the hi-yard perimeter wall is completed. IAEA ---- There were 31 C-Mod related papers at the 24th IAEA Fusion Energy Conference in San Diego, CA, last week including 8 oral and 23 poster presentations. Papers and presentations from this meeting will be made available soon at: http://www.psfc.mit.edu/research/alcator/pubs/iaea/2012/index.htm Oral presentations included: Thomas Eich (MPI-Garching) - Scaling of the Tokamak near Scrape-off Layer H-mode Power Width and Implications for ITER Martin Greenwald - Highlights of the Alcator C-Mod Research Campaign Rich Groebner (GA) - Improved Understanding of Physics Processes in Pedestal Structure, Leading to Improved Predictive Capability for ITER Amanda Hubbard - Progress in Performance and Understanding of Steady ELM-free I-modes on Alcator C-Mod Katsumi Ida (JAEA) - Towards an Emerging Understanding of Nonlocal Transport Sadayoshi Murakami (Kyoto University) - Study of Toroidal Flow Generation by the ICRF Minority Heating in the Alcator C-Mod Plasma John Rice - Rotation Reversal and Energy Confinement Saturation in Alcator C-Mod Ohmic L-mode Plasmas: A Novel Transport Bifurcation Stephen Wukitch - Rotated 4-strap ICRF Antenna: Design and Initial Results Advanced Divertor PDR --------------------- Preparations are being made for a Preliminary Design Review (PDR) of the new Advanced Divertor for C-Mod scheduled for October 22nd. This upgrade will prepare C-Mod for several second discharges with over 8 MW of input power, operating at steady-state temperatures of up to 600 C. Operation with the Advanced Divertor will provide vital new information on the retention of hydrogenic species under ITER-like and reactor-relevant conditions. ICRF Systems ------------ At the end of the last campaign, persistent faulting at relatively low power was observed on the FA antenna. A careful inspection of the antenna transmission line, phase shifter, and stub tuners, using both visual and time-delay-reflectometer techniques, has begun. An inspection of the high power switch for this system indicated a misalignment issue that is currently being corrected. An inspection the new FFT system (two FFT units) for the E-Port antenna that faulted at low power shortly after installation has also begun. Some damage to one of the units, which very likely occurred during shipment, has been found on a mechanical fastener and in the water cooling system. Inspections thus far of the second unit have found it to be in good condition. Lower Hybrid System ------------------- The new LH four channel fast thermocouple transmitter boxes have been calibrated. Last week, the Collector Over-temperature System (COTS) cabinets were modified to accept the new multi-pin connectors for the Fast TC system. Wiring modifications for the four cabinets have been specified. More than half of the collector TC pipe nipples are ready for installation. Diagnostic Neutral Beam Systems ------------------------------- The high voltage transformer has been removed from the cell and placed in one of our diagnostic labs for inspection. Several failed components have been identified that contributed to the performance limitations experienced during plasma operation. This work will continue this week. Diagnostics ----------- Following the end of the FY12 plasma campaign, AGNOSTIC continues to measure PFC surface properties of the inner wall. Both the TF and EF4 coils have been used to steer the beam poloidally and toroidally for high-spatial resolution measurements of the inner wall PFCs. Potential changes to the PFCs since the end of the campaign due to ECDC and deuterium and nitrogen backfills for Thomson scattering calibrations were also investigated. Remote Participation, Travel, and Visitors ------------------------------------------ Bob Ellis visited MIT last week to work on the Advanced Divertor. In preparation for the upcoming Preliminary Design Review, electromagnetic and thermal analyses were discussed, and schedule estimates were reviewed. Allen Reiman, PPPL, also visited last week. On Thursday he gave an informal seminar titled "Calculation of the Effect of a Small Nonaxisymmetric Field in a Tokamak", on work related to the FY2012 FES Theory Milestone. C-Mod was well represented in San Diego, CA, last week for the IAEA meeting, including from MIT, Paul Bonoli, Catherine Fiore, Robert Granetz, Martin Greenwald, Nathan Howard, Amanda Hubbard, Jerry Hughes, Yijun Lin, Yunxing Ma, Earl Marmar, Miklos Porkolab, Matthew Reinke, John Rice, Syun'ichi Shiraiwa, James Terry, Gregory Wallace, Graham Wright, and Stephen Wukitch. Luis Delgado-Aparicio (PPPL), Chuck Kessel(PPPL), Rich Groebner (GA) Katsumi Ida (JAEA), Sadayoshi Murakami (Kyoto University), Pat Diamond (UCSD/NFRI), Jim Myra (Lodestar), Bob Harvey (CompX), Thomas Eich (MPI-Garching), Angelo Tuccillo (ENEA-Frascati), George Sips (EFDA-JET), Tuomas Tala (VTT, Finland), Arne Kallenbach (MPI-Garching), and Punit Gohil (GA) also attended and gave C-Mod related presentations. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly