NEW DIRECTIONS OF X-RAY SPECTROSCOPY APPLIED TO HOT, LOW DENSITY PLASMAS

Abstract
X-ray spectroscopy has frequently been used as a major tool for diagnosing the center hot part of fusion plasmas. High resolution X-ray line spectra and broad band X-ray emission spectra are used to deduce ion temperatures and impurity concentrations in the plasma. X-ray lines mostly studied are the n=2 to 1 transitions produced by electron impact excitation. However, time resolved spectra observed during the full plasma discharge have shown the importance of other excitation mechanisms. These new results are discussed and implications towards next generation of X-ray instrumentation in plasma diagnostics is outlined.