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Initial Electron Temperature Measurements on TCSU

Author: Raymond P. Golingo
Requested Type: Poster Only
Submitted: 2009-12-04 20:54:42

Co-authors: K.Y. Lee

Contact Info:
University Of Washington
120 AERB Box 352250
Seattle, WA   98195-2
USA

Abstract Text:
A multi-point Thomson scattering system using a ruby laser has been designed and is being installed on the Translation, Confinement, and Sustainment Upgrade (TCSU) experiment. FRC plasmas are formed and sustained using rotating magnetic fields. Improvements to the vacuum system have lead to decreased impurity levels and increased the temperature of the plasma. Presently, total temperatures of 150 eV and density of about 10$^{19}$ m$^{-3}$ are measured in the device using pressure balance and interferometry measurements. A multi-point Thomson scattering system will be able to provide information on localized electron temperatures. The Thomson system is capable of measuring 5 spatial points along the bottom half of the TCSU chamber. Initial measurements of the multi-point system will be made at 7 cm increments. The present design allows for a 3.5 cm spatial resolution by simply placing the fibers into different slots. A single structure has been built to ensure the collection optics and the laser stays well aligned. The collected light from each spatial location is resolved with GA polychromators that use PPPL pre-amplifier modules. The spectral response of each of these units has been characterized. Techniques to relate the scattered light signal and background signals from the pre-amplifiers will also be discussed. The system is presently being installed on TCSU. Initial measurements of the electron temperature at one location in the experiment with planned upgrades to the TCSU Thomson scattering system will be presented.

Characterization: A1,A3

Comments:
Please place the posters from J.A Grossnickle, K.M. Velas, and R. P. Golingo in the following order

1. J.A Grossnickle
2. K.M. Velas
3. R. P. Golingo