Toroidal Field Profile Measurements of SSPX Spheromaks Using the Transient Internal Probe
Abstract
The Sustained Spheromak Physics Experiment has been producing temperatures in excess of 100 eV which often have a peaked pressure profile. This occurs while the coaxial gun continues to feed current at the edge to hold the field roughly constant or in a slow, controlled decay. The Transient Internal Probe (TIP) diagnostic is now installed on SSPX and is being used to make field profile measurements during this hot driven phase. The diagnostic consists of a cylindrical verdet glass that is launched through SSPX at over 1.5 km/s. While in transit, it is illuminated from the front by an argon laser. After passing through the probe the light is retro-reflected to an ellipsometer where it is analyzed for polarization rotation due to the magnetic field at the probe. As of this writing, we are testing the diagnostic with plasma to adjust alignment, signal levels, and system timing; internal field profile measurements are expected later this summer, with the data being incorporated into MHD reconstruction of the current profile to help determine the beta and stability of the spheromak plasma. ^a University of Washington, Seattle WA, 98195 This work was performed under the auspices of US DOE by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..DPPGP1074H