Alcator C-Mod Weekly Highlights Dec 13, 2004 FY 2005 weeks of research operation planned: 14 weeks, completed: 0 weeks. We are currently up-to-air with the primary goal of installing the lower hybrid launcher. In addition, a large number of in-vessel activities are ongoing in support of ICRF and diagnostic systems. Maintenance and upgrades to diagnostic and power systems are also in progress. Physics -------- The C-Mod Ideas Forum, which began Dec 2, was completed on Monday, Dec 6. A total of 113 ideas were submitted representing twelve institutions, and the Forum was extended to three days so that they could all be presented. Participation in the Forum was also conducted by video and audio links from all around the country. Follow-up meetings in each of the task groups will be held over the next few weeks to evaluate proposals and define priorities for experiments to be undertaken during the next campaign. See the Ideas Forum web page http://www.psfc.mit.edu/cmod/sciprogram/ideas2005/index.html for more information. Operations ----------- The alternator neutral ground installation continues. The neutral grounding resistor is scheduled to arrive this week. A detailed report is being prepared on the changes to the grounding system, asn how the changes will affect other C-Mod systems, as suggested by our review committee. In-vessel work continued with completion of the modified retro-reflector mounting for the polarimetry diagnostic. Work on the bracket for mounting the cryopump baffle is in progress. Scheduled maintenance was carried out on the UPS systems. Diagnostics ----------- Bragg cell drive components for the polarimeter diagnostic have been installed in the chassis. The majority of power wiring and rf cabling was installed as well. Completion of the drive system awaits biasing circuitry for power output adjustments and the delivery of the front panel. Polarimeter mirror mounts and hardware have been machined and sent to the vendor for passivation. ICRF Systems ------------ Documentation of the power supply for the fast ferrite tuner (FFT) system is underway; several undocumented features were apparently incorporated by the vendor during development. We hope to resume power testing of this unit this week. Transmitter #3 FPA tube has been replaced with one of the new tubes delivered last month. Transmitter #2 FPA has been disassembled in order to replace its tube. Long Pulse DNB System ---------------------- The new control rack for the DNB has arrived and the vacuum gauge controllers, the PLC rack, and other hardware are being prepared and mounted. Lower Hybrid System ------------------- The last of the Transmitter Protection System (TPS) cards have been finished and installed. These are the optical interface cards that connect the TPS with the CPS (coupler protection system). The CPS equipment rack wiring is proceeding. The filament monitoring electronics for cart #2 have been installed. Both the front panel meters and the PLC displays have been calibrated against voltage and current measurements made at the klystron. Clean-up of the MIT#4 coupler has been completed, and its final leak-check before installation has been successfully completed. Brazing of the MIT#3 coupler was completed last Thursday, and it also was leak-checked successfully. The remaining two MIT couplers (#1 and #2) have completed machining operations and pre-braze processing of #1 has been completed. The MIT#1 coupler was brazed over the weekend and is now undergoing a leakcheck. The MIT#2 coupler is being prepared for brazing later this week. Travel and Visitors ------------------- Joe Snipes spent 6 - 8 December at the European Fusion Physics Workshop where he presented a talk entitled "Energetic Particle Physics Studies on Alcator C-Mod". He then went to CRPP (Lausanne) to work with Ambrogio Fasoli through our collaboration with JET on the new TAE antennas for JET. These are being built at the CRPP and should be ready for testing. Bruce Lipschultz represented the C-Mod group at two meetings last week. At the first meeting entitled 'Plasma-Facing Component Technology Meeting' held from December 6-8, 2004 in Livermore, California, Lipschultz gave a presentation describing the C-Mod program in general and the first-wall interaction experience in detail. The organizers of the meeting particularly wanted to have a talk on C-Mod because of the renewed interest in high-z materials by the Technology side of DoE. Dennis Whyte, from the U. Wisc., also gave a presentation about the analysis of C-Mod tiles for B, D and Mo coverage around the vessel. This is new work that showed the poloidal distribution of the boronization on the Mo tiles as well as the level of D retained. Bruce Lipschultz went from California to a meeting of the IEA/ITPA coordinating committee, held outside of Oxford UK. He represented the C-Mod group as well as the ITPA SOL/divertor committee, of which he is co-chair. This meeting, held on Dec 8-10, was held to review proposals by the ITPA committees and collaborators to do joint experiments across tokamaks. The heads of machines were there to understand the proposals and indicate whether they were willing to support such experiments in 2005. C-Mod was part of 21 proposals for joint work. Most proposals were enthusiastically endorsed thus enhancing the possibility that such experiments will be run. In between the two meetings, on Wednesday, the 8th, Bruce Lipschultz visited the JET site for discussions with Guy Matthews on the collaborative work both in the area of SOl transport and on the development of W-brush tiles. David Mikkelsen visited MIT this week to study changes in temperature profile shape in Alcator C-Mod plasmas; interesting discharges were provided by Catherine Fiore, Amanda Hubbard, and John Rice. It has now been established that in discharges with steady toroidal magnetic field it is possible to reliably detect 3-5% changes in the temperature gradient scale length in the region where ITBs form. A catalogue of systematic temperature profile behavior is being developed with the aim of designing an experiment to test the predictions of gyrokinetic microinstability codes. In addition, simulations of lower hybrid current drive were discussed with Paul Bonoli. Ron Bravenec, UT-FRC, is in the middle of a two week visit. He is completing pre-campaign calibration of the BES diagnostic. Walter Davis (GE) spent two days on site this week to perform testing/calibration of the Limit-Amp LOD-TRAC module as well as review the progress of the alternator neutral ground resistor installation. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly