Abstract

Magnetic fusion plasmas have temperatures ranging from several tens of electron volts at the edge up to several kiloelectron volts at the center. Electron densities typically vary from 1 to 10 × 10¹³/cm³. Spectroscopic techniques using wavelengths from the x-ray through the visible regions are employed to measure a number of parameters.¹ These quantities include, but are not restricted to, plasma temperatures, radiated power, impurity content and transport, radial electric fields as inferred from plasma rotation, neutral hydrogen densities, and rotational transforms of magnetic fields. In addition to passive spectroscopy, active techniques are used for enhancing spectroscopic capabilities. Introduction of trace amounts of nonintrinsic impurities by laser ablation, excitation by charge exchange between energetic hydrogen beams incident on highly ionized impurities, laser-induced fluorescence, and excitation of lithium introduced in a beam or as a pellet have all been employed for making one or more types of measurement. In particular, charge exchange from hydrogen beams has become widely adopted as the standard method of measuring ion temperatures, plasma rotation, and concentrations of fully ionized low-Z impurities.²

© 1989 Optical Society of America