Performance Study of the Two-Stage Light Gas Gun for Active TIP Probes
Abstract
The Transient Internal Probe (TIP) is a diagnostic for measuring local parameters across a cord of a plasma using a refractory-clad probe that traverses the plasma at a speed of 1.8 km/sec, fast enough that heating of the probe will not cause significant ablation during transit. To date, TIP has used passive magneto-optic probes illuminated during transit by a polarized laser, and having a retroreflector to return light to an ellipsometer after a double-pass through the probe. One component of the local magnetic fields is deduced by Faraday rotation of the return light. Electro-optic probes have also been studied. A richer set of parameters, potentially including plasma temperature and density, would be afforded by active TIP probes, using on-board microelectronic sensors; information would be encoded by modulation of radiation generated on-board (i.e., LED or laser diode). This approach also avoids distortion of signals from passive probes created by stress-induced polarization effects. At issue is the survivability of on-board microelectronics under acceleration of the probe by a two-stage light-gas gun. This paper describes analytical and experimental studies of acceleration of TIP probes versus gun operating parameters. The results will be used to determine optimal gun parameters for minimizing acceleration stress, while still reaching the needed probe speeds of 1.6-1.8 km/sec.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2002
- Bibcode:
- 2002APS..DPPUP1033K