Alcator C-Mod Weekly Highlights December 14, 2001 The Alcator C-Mod Ideas Forum was held this week. Work continued on the inspection, Lower Hybrid MIE Project, ICRF systems, and the inner divertor. Alcator C-Mod Ideas Forum ------------------------- The Alcator C-Mod Ideas Forum was held on December 12 and 13. The purpose of the forum was to provide an opportunity for presentation of specific ideas appropriate for experiments during C-Mod's 2002 run campaign. As usual, the Forum was open to all interested parties, including current and potential future collaborators. Ideas were solicited in six "Task-force-areas": Advanced Tokamak Issues Burning Plasma Support Issues Transport Physics Divertor/Edge Physics MHD Physics RF Physics A total of seventy ideas were presented. Ideas came from nine different institutions. In addition to the Plasma Science and Fusion Center at MIT, the other eight contributing institutions were: General Atomics FRC at the Univ. of Texas PPPL UCSD LLNL Univ. of Toronto Univ. of Maryland Colorado School of Mines This was the first Ideas forum for which all presentations were electronic, with full PictureTalk, audio, and video feeds. This accommodated a number of remote presentations from GA, PPPL, and U of Texas. All of the presentations are available for download as pdf files on the WEB at http://www.psfc.mit.edu/people/terry/Forum_agenda.html Additional information about the Forum can be found at http://www.psfc.mit.edu/people/terry/Ideas_Forum.html The Ideas will now be organized and prioritized for development within each of the Task-force-areas. Inspection ---------- The TF inspection has been completed, and all TF components are ready to be re-installed. Final checks and measurements of the OH coax are expected to be completed next week at which point reassembly of Alcator C-Mod will begin. MHD Antennas ------------ The Active MHD antennas have been redesigned to move them further from the plasma, to make the design more robust mechanically and electrically, and to cover them with boron nitride tiles to withstand high plasma heat loads. The new design employs a stainless steel Bitter-type plate per turn insulated with ceramic coated stainless steel washers and firmly bolted together with ceramic coated bolts. This overcomes potential cracking of ceramic tube insulators in the old design and makes a stronger antenna to better withstand disruption forces. The new design also permits taking apart the antenna should maintenance ever become necessary. Due to the high cost of the boron nitride protection tiles and the limited budget, only two Active MHD antennas will be built this up-to-air and installed at GH port. The remaining two antennas will be built during FY2003 to be installed at EF port next to the E-port ICRF antenna. Prototypes of the amplifiers to drive the antennas from 1 kHz to nearly 1 MHz have been built and higher power versions capable of driving 20 A of current in the antennas are being designed. A prototype matching network was also built that permits 20 A of current to be driven by the existing 400 W amplifier that operates from 80 kHz - 2.7 MHz. These antennas will be used to drive stable modes in the plasma to determine the proximity of the plasma to different types of unstable modes such as lower frequency tearing modes or high frequency Toroidal Alfven Eigenmodes in the presence of an ICRF driven fast ion tail. Lower Hybrid MIE Project ------------------------ Wiring of water interface instrumentation is continuing. Wiring on the remaining two Transmitter Control and Protection Cabinets is nearly complete. Testing is underway on the filament power supply power and control circuits. The water system for cooling the klystrons is expected to be ready for tests in the next few days. The lines have been filled with water. Work on the pump controllers is proceeding. Work continues on the low power microwave racks and associated components. We continue to develop and test PID software and hardware needed for the klystron phase and power control system. ICRF Systems ------------ The design of the demodulator board has been completed, and a circuit board has been developed and sent out to be fabricated. This board will support not only the demodulator electronics but also the electronics required to generate the local oscillator during operation from 40 to 80 MHz. These local oscillator frequencies will be remotely programmable. DNB and Related Diagnostics --------------------------- The purchase order for transport and installation of the new diagnostic beam is being processed. We expect delivery of the beam to MIT in late January or early February. Work continued on preparations for the beam including design of the mechanical support system. A solid model of the F-Port horizontal flange is nearly done. Work on the PLC interface for the vacuum system is proceeding. The power distribution system for the beam is nearly designed, and we expect to begin installation of power components in the cell next week. Inner Divertor -------------- Work continued on installation of thermocouples on the inner divertor C-Plates. Installation of all girdle plates is expected to be complete by the end of next week. Tile, cable, probe, and gas feed line installation will then proceed for several more weeks. Travel and Visits ----------------- Joel Hosea, PPPL, was at MIT 12/12-13 for the Ideas Forum and Lower Hybrid discussions. Stewart Zweben and Raffi Nazikian, PPPL, Ron Bravenec, UTexas, and Vincent Chan, General Atomics, also attended the ideas forum at MIT.