Microwave tokamak experiment (MTX) status and plans

The MTX program has focused on ohmic operation of the tokamak (Alcator-C moved from MIT), construction of the free-electron laser (FEL) microwave source and quasi-optical transport system, and preparation for the first measurements of absorption. The first microwave pulses from the FEL to the tokamak are planned for this spring. Measurements of the absorption of single high peak power pulses (140 GHz, 2 GW, 20 ns) will be done through September. Starting in October 1989, the FEL will be upgraded to generate pulses at 5 kHz for 10 ms, providing an average power 0.5-1 MW. A year later, the system will be further upgraded to 250 GHz and 2 MW average power. Following the upgrade to multiple-pulse operation and subsequent absorption measurements, experiments on heating and transport will be carried out. Attention will be directed to heating in peaked density profiles generated by pellet injection and to the effects of varying the power deposition profile. Plans include heat-pulse experiments and other measurements of local transport. Density fluctuations will be monitored by forward scattering of the far-infrared interferometer beams. Longer-term plans include noninductive current drive and MHD control and are outlined