Microwave tokamak experiment (MTX) status and plans

Summary Form only given, as follows. The MTX program has focused on ohmic operation of the tokamak (Alcator-C), 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 were planned for the spring of 1989. Measurements of the absorption of single, high-peak-power pulses (140 GHz, 2 GW, 20 ns) will follow. Thereafter the FEL will be upgraded to generate pulses at 5 kHz for 10 ms, providing an average power 0.5-1.0 MW, and then further upgraded to 250 GHz and 2 MW average power. Several diagnostics have been prepared for the initial microwave absorption experiments. These include microwave measurements, fast X-ray and cyclotron emission from the heated electrons, Thomson scattering from the tail, and fast magnetic probe measurements. Modeling of absorption and wave refraction have been done, and a computer database has been established for rapid analysis of the experimental results and comparison with theoretical predictions. 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. >