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Abstract

The signature of prompt C/X excited radiation, a large increase in line emission with rise-time determined by injector switch-on time, has been observed in DITE for carbon and oxygen impurity lines in the spectral region 100-650 A. These lines originate from energy levels most efficiently populated by C/X. In contrast, in both the X-ray and visible regions of the spectrum no clear signature of prompt C/X is observed. Line emission from hydrogen-like carbon and oxygen ions appears to be dominated by electron impact excitation. Spatially resolved measurements in the visible region have identified the presence of C/X excited line emission from carbon, however from the peripheral regions of the plasma, outside the beam illuminated volume; it is interpreted as being due to electron impact excitation of CVI. Similar behaviour of visible carbon lines has been recently observed in ASDEX. The interpretation of the carbon visible line emission data (C/X and electron impact excited components) demands statistical redistribution in the population of the sublevels of the n = 8 state, to obtain signals of reasonable impurity concentration (approximately equal 1% n-e). C/X spectroscopy experiments are continuing on DITE, with viewing geometry and plasma conditions tailored to optimize C/X line intensities.

Additional information

Authors: DUVAL B P, EURATOM-UKAEA (UK);FIELDING S J, EURATOM-UKAEA (UK);HAWKES N C, EURATOM-UKAEA (UK);HUGILL J, EURATOM-UKAEA (UK);PEACOCK N J EURATOM-UKAEA (UK), EURATOM-UKAEA (UK)
Bibliographic Reference: 12TH EUROPEAN CONFERENCE, BUDAPEST (HUNGARY), SEPT. 2-6, 1985 VOL. 1, PP. 203-206
Record Number: 1989125020400 / Last updated on: 1987-02-01
Category: PUBLICATION
Available languages: en