Neutral beam diagnostics for the HT-7 tokamak

Abstract

A diagnostic neutral beam will be added to the diagnostic set so that charge-exchange recombination spectroscopy (CXRS) can be used to acquire ion temperature and rotation, and to study the role of the ion thermal transport, the radial electric field, and turbulence in the high performance HT-7 plasma. In normal operation, the diagnostic neutral beam (DNB) can produce 5.5 A of extracted beam current in hydrogen at an energy of 50 keV with a pulse length of 0.1 s. D and He beams can be produced as well. The beam can be modulated at 0.5 kHz. The CXRS system will have 45 spatial observation chords and employ a spectrometer, which can acquire spectra at the rate of 100 Hz. In this article, the capabilities and implementation of the DNB and CXRS systems are presented.