Main ion charge exchange recombination spectroscopy on C-2W FRC plasmas.

A main ion charge exchange recombination spectroscopy (mChERS) diagnostic has been developed to measure the velocity and temperature of the main deuterium ions in the C-2W (also called Norman) field-reversed configuration (FRC) device. A modulated diagnostic neutral beam (DNB) of hydrogen with 40 keV full energy and a nominal current of 8.5 A provides the charge exchange signal. The DNB can achieve a fast modulation frequency of up to 10 kHz, a rare attribute to find on other fusion devices, which defines the time resolution of mChERS. Currently, the mChERS diagnostic provides simultaneous measurements at five spatial locations in the FRC plasma using a high-speed camera. The design and capabilities of the mChERS system are presented along with first experimental data.