High-average-power millimeter-wave FEL for plasma heating using the ETA-II accelerator

The Microwave Tokamak Experiment (MTX) is under construction at Lawrence Livermore National Laboratory to investigate the feasibility of intense, pulsed microwave radiation for plasma heating on future ignition tokamaks. A high-average-power free-electron laser (FEL) will use the Experimental Test Accelerator (ETA-II), a linear induction accelerator, in combination with an advanced high-field wiggler, to produce 1-2 MW of power at 1-2-mm wavelengths for periods of up to 0.5 s. The design of the FEL, termed the Intense Microwave Prototype (IMP), is described, along with the status and major issues associated with the experiment.<>