Central Thomson scattering upgrade on DIII-D
- Lawrence Livermore National Lab., CA (United States)
- General Atomics, San Diego, CA (United States)
The existing 36 channel Thomson scattering system on the DIII-D tokamak measures the plasma temperature and density in the core region. However, with the recent interest in core peaked density profiles, coverage needs to be extended into the magnetic axis. This paper addresses the technical issues involved with extending the viewing region from a major radius of 194 cm to 165 cm. At least one of the existing seven core laser beams will be rerouted to probe the plasma horizontally instead of vertically. To do this, a rigid extension of the existing laser/collection optics tower will be built to route the laser to a nearby tangential port. A fiber bundle array from one of the two existing core plasma collection optics sets will be rotated to allow up to 10 of the 36 core channels to view along this new beam path. A new in-vessel absorbing glass laser dump must be developed since there are no appropriate laser beam exit ports. The close proximity of this laser dump to the viewing region presents stray light issues that must be resolved to allow for an accurate density calibration using Rayleigh scattering in argon gas.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 564187
- Report Number(s):
- GA-A22722; CONF-971065-; ON: DE98001864; TRN: 98:003187
- Resource Relation:
- Conference: 17. IEEE/NPSS symposium on fusion engineering, San Diego, CA (United States), 6-10 Oct 1997; Other Information: PBD: Nov 1997
- Country of Publication:
- United States
- Language:
- English
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