Title :
An assessment of the lifetime of Faraday shield elements
Author :
Caughman, J. B o, II ; Ruzic, D.N. ; Hoffman, D.J. ; Langley, R.A. ; Lewis, M.B. ; Ryan, P.M.
Author_Institution :
Illinois Univ., Urbana, IL, USA
Abstract :
The interaction of plasma with RF fields from an ion cyclotron range of frequencies (ICRF) antenna has been studied to estimate the amount of Faraday shield erosion expected in normal ICRF heating (ICRH) operation. Plasma parameters and ion energies have been measured in the near field of an antenna and used in a model to estimate the erosion rate of the Faraday shield surface. Experiments were conducted on the RF Test Facility (RFTF), a magnetic mirror device at Oak Ridge National Laboratory (ORNL), using a single-strap resonant loop antenna with a two-tier Faraday shield. Plasma parameters and ion energies have been correlated with the antenna current and used in a computational model of the plasma sheath to predict the amount of erosion expected from the Faraday shield elements exposed to plasma. Predictions of light-ion sputtering of candidate Faraday shield materials are presented
Keywords :
fusion reactor materials; fusion reactor safety; plasma diagnostics; plasma sheaths; shielding; sputtering; Faraday shield elements; ICRF heating; RF Test Facility; RF fields; antenna current; erosion rate; ion energies; lifetime; light-ion sputtering; magnetic mirror; near field; plasma parameters; plasma sheath; single-strap resonant loop antenna; Antenna measurements; Cyclotrons; Frequency estimation; Heating; Magnetic resonance; Plasma devices; Plasma materials processing; Plasma measurements; Plasma sheaths; Radio frequency;
Conference_Titel :
Fusion Engineering, 1989. Proceedings., IEEE Thirteenth Symposium on
Conference_Location :
Knoxville, TN
DOI :
10.1109/FUSION.1989.102368
