Evolution of low-density Thomson scattering on ELMO Bumpy Torus
The ELMO Bumpy Torus (EBT) confines a low-density, steady-state, microwave-driven plasma. On the basis of favorable initial diagnostic results, major machine upgrades: increases in microwave power and magnetic field: were initiated, and the feasibility of Thomson scattering was considered. From the time of the first laser measurements, in which a two-point spectrum was integrated during 30 or more Q-switched pulses, the Thomson scattering system has evolved into a reliable diagnostic tool that is able to obtain scans along 20 cm of the plasma diameter and to determine the central electron temperature at densities as low as 2 x 10/sup 11/ cm/sup -3/. Based on a 25-J ruby laser and a seven-channel polychrometer, the present system (1) reveals a bulk plasma with T/sub e/ = 20--100 eV and n/sub e/ = 5--10 x 10/sup 11/ cm/sup -3/ and (2) indicates a suprathermal tail consistent with x-ray measurements. With up to 200 kW of microwave power inside the machine, major problems to overcome were radiation damage to optical materials (< or =3000 R/h) and plasma coating of windows and dumps.
- Research Organization:
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
- OSTI ID:
- 5639459
- Journal Information:
- Rev. Sci. Instrum.; (United States), Vol. 56:5
- Country of Publication:
- United States
- Language:
- English
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Thomson scattering on ELMO Bumpy Torus
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Related Subjects
ELMO BUMPY TORUS
PLASMA DIAGNOSTICS
LASER SPECTROSCOPY
THOMSON SCATTERING
ELECTRON DENSITY
ELECTRON TEMPERATURE
EXPERIMENTAL DATA
OPERATION
RUBY LASERS
WINDOWS
BUMPY TORI
DATA
ELMO DEVICES
INELASTIC SCATTERING
INFORMATION
LASERS
MAGNETIC MIRRORS
NUMERICAL DATA
OPEN PLASMA DEVICES
OPENINGS
SCATTERING
SOLID STATE LASERS
SPECTROSCOPY
THERMONUCLEAR DEVICES
700102* - Fusion Energy- Plasma Research- Diagnostics