Ion temperature measurement from Doppler broadening of He-like nickel lines
Uncertainties in deducing central ion temperatures in the JET tokamak from the line width of the helium-like nickel resonance line emitted by impurity nickel ions in the plasma centre are examined. The statistical errors in fitting a Voigt function to the experimental line profile data points produce estimated ion-temperature errors of typically less than 5%. Other major sources of errors include (i) averaging of the ion temperature over the spectrometer line-of-sight through the plasma, (ii) the effects of dielectronic satellites on the line profiles and (iii) the effects of bulk plasma toroidal rotation. The magnitudes of these errors are quantified for various plasma conditions and shown to be small (<=10%) for JET plasmas. Error (i) is opposite in sign to errors (ii) and (iii), leaving total estimated ion-temperature errors (including statistical effects) of <15%.
Bibliographic Reference: Report: JET-P(88)36 EN (1988)
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 198910437 / Last updated on: 1994-12-01
Original language: en
Available languages: en