Ion energy and plasma measurements in the near field of an ICRF antenna
Plasma properties and ion energies have been measured in the near field of an ICRF antenna to determine the effects of rf fields in a magnetized plasma sheath on the energy of ions incident on the surface of the Faraday shield. A resonant loop antenna with a two- tier Faraday shield was used on the RF Test Facility at Oak Ridge National Laboratory (ORNL). The magnetic field near the antenna is /approximately/2 kG, and the plasma density is /approximately/10/sup 11/ cm/sup /minus/3/ with an electron temperature of 6-10 eV. The time-varying floating potential was measured with a capacitively coupled probe, and the time-averaged electron temperature, electron density, and floating potential were measured with a Langmuir probe. Both probes were scanned poloidally in front of the antenna, parallel to the current strap. Diagnostics for measuring ion energies included a gridded energy analyzer located directly below the antenna. Measured ion energies are compared with predictions from a computational model for determining the energy and angular distribution of ions incident on a surface in a magnetized plasma sheath with a time-varying plasma potential. 7 refs., 3 figs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6244269
- Report Number(s):
- CONF-8905120-6; ON: DE89011611
- Resource Relation:
- Conference: 8. topical conference on radio frequency power in plasmas, Irvine, CA, USA, 1 May 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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