Alcator C-Mod Weekly Highlights September 15, 2003 Work continued on Lower Hybrid and ICRF system last week. Reassembly of the alternator is scheduled to be completed this week. The C-Mod Ideas Forum was held last week at MIT. Ideas Forum ----------- The C-Mod Ideas Forum was held on September 10, 11, and 12 to aid in planning the FY04 C-Mod operating campaign. The purpose of the Forum was to provide an opportunity for presentation of specific ideas appropriate for experiments during the campaign. The Forum was open to all interested parties, including current and potential future collaborators. The agenda of the Forum and links to the ninety-eight presentations can be found at http://www.psfc.mit.edu/people/terry/Ideas_Forum_2003/forum_agenda.html Ideas were submitted by personnel from PPPL, U. Texas, U. of Wisconsin, IPP-Garching, LANL, GA, RFX, LLNL, ORNL, CRPP, and MIT. Follow-on meetings of the Topical Science and Integrated Thrust Groups, in the coming few weeks, will determine initial prioritization as the next step leading to mini-proposal generation and run-time allocations. Operations ---------- NSTAR opened our primary 13.8 kV breaker last week for annual maintenance. During this time, in preparations for plasma operations, we performed inspections and maintenance on much of the hi-yard equipment, including vacuum breakers and instrumentation. Completion of all C-Mod vacuum work is expected by the end of this week, after which a final pumpdown and leak check will be performed. Cool down, bake, and ECDC activities will then follow, with first plasma operation expected in early October. Alternator ---------- GE repeated the DC stepped voltage test to 28 kV on the alternator stator last Monday. This test was followed by a hi-pot proof test to 36.7 kV. All stator windings passed these tests with excellent I/V characteristics. As a final test of the stator windings, an AC hi-pot to 21.6 kV RMS (a factor of 1.5 above the working voltage) was done by GE on Wednesday. The results were again very positive and GE has recommended the alternator be returned to service. AC hi-pots are considered to be the most probative tests of the stator windings and an excellent predictor of safe in-service operation. With the concurrence of DoE OFES and the MIT Vice-President for Research, we have instructed GE to proceed with reassembly, which has now begun. GE is using a two shift schedule and expects to be finished by the end of this week. Installation of the drive motor, instrumentation, and other support hardware by C-Mod personnel will require one additional week. ICRF Systems ------------ General maintenance of transmitters, control electronics, and switch gear continued. Preparations of the control system instrumentation for 50 MHz operation began. Reassembly of transmission line components in the C-Mod cell continued. Lower Hybrid Systems -------------------- The modified PLC and operator interfaces have been installed and tested on the LH system. Some programming bugs were located and corrected. Measurements of the PLC analog inputs will be made and calibration factors will be determined. The Lower Hybrid Forward Wave Guides have now been reassembled at PPPL. Loss measurements have been performed, and the losses are acceptable. The upper FWG will be brought to MIT on Monday for high-power RF tests; Nevell Greenough (PPPL) will participate in the testing. Both MIT and PPPL are continuing to refine and compare finite element analysis mechanical/thermal models of the coupler. Measurements of the coefficient of thermal expansion of both the ceramic and titanium coupler materials have been started, and the results and differences in measurement techniques are being discussed. Coupon tests of braze materials are underway, and final preparations are being made to remove the "old" ceramic windows from the existing coupler which is expected to take place next week. Travel and Visits ----------------- Martin Greenwald attended the 18th International Conference on Numerical Simulation in Plasmas to deliver a review talk titled "Beyond Benchmarking - How Experiments and Simulations Can Work Together in Plasma Physics". This review talk may be found at http://www.psfc.mit.edu/people/g/icnsp03-talk.pdf Several collaborators from PPPL were at MIT last week. Stefano Bernabei came to attend the C-Mod Ideas Forum on 9/11 and Stewart Zweben visited from 9/8-12, also participating in the Ideas Forum. Gerd Schilling was at MIT from 9/9-12 for the Ideas Forum and Lower Hybrid program discussions. Martha Redi was at MIT on Sept 5, 8, and 9 to meet with Catherine Fiore, Steve Wukitch and others for discussions about the RF ITB gyrokinetic simulation work and Ohmic H-mode ITB data for upcoming publications and conferences. Bill Rowan, U. Texas, also visited last week for the Ideas Forum.