A magnetically-guarded electrostatic probe
- Emporia State Univ., KS (United States). Physics Dept.
Electrostatic ``Langmuir`` probes continue to be one of the most important and most widely used tools for making measurements in plasmas. Although Langmuir probes are routinely employed in the boundary region of fusion plasmas, their use is limited by the thermal damage that they suffer and by their perturbing influence on the plasma. Similar problems restrict the use of biased electrodes employed to modify the radial electric field and improve plasma confinement. Metallic current-carrying ``hairpins`` have been used as supports in internal ring machines and as limiters in toroidal plasma devices. The hairpin is oriented so as to divert the ambient plasma and its confining magnetic field, causing them to pass harmlessly around the hairpin ``obstacle`` itself. In the present experiments the hairpin consists of one or several turns of fine metal tubing through which water can pass for cooling purposes. The outside of the hairpin can be electrically insulated with a ceramic sheath. A magnetically-guarded hairpin can support a Langmuir probing electrode with reduced disturbance of the plasma and less thermal damage to the probe.
- OSTI ID:
- 142422
- Journal Information:
- IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 6 Vol. 21; ISSN ITPSBD; ISSN 0093-3813
- Country of Publication:
- United States
- Language:
- English
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