AN EXPERIMENTAL INVESTIGATION OF CHEMICAL SPUTTERING OF CARBON IN A TOKAMAK DISCHARGE
An experiment has been undertaken to see if chemical sputtering of carbon can be directly observed under tokamak operating conditions. The test material consists of a well instrumented probe limiter which can be heated up to 900 degrees C under steady state conditions and to > 1200 degrees C with additional plasma heating during a discharge. The carbon released from the limiter is monitored spectroscopically using a visible spectrometer and a CCD camera with interference filters. Measurements have been made from 20 degrees C to 700 degrees C in steady state conditions and up to 1200 degrees C with plasma heating. Within experimental error there is no change in the carbon production rate over the whole temperature range. Compared with beam experiments the inferred chemical sputtering yields are low. A semi-empirical model predicts such low yields at high current densities of incident ions.
Bibliographic Reference: WRITE TO THE LIBRARIAN, UKAEA, CULHAM LABORATORY, ABINGDON, OXON OX14 3DB (UK), MENTIONING REPORT CLM-P775, 1986
Record Number: 1989124140000 / Last updated on: 1987-01-01
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