Evolution of low-density Thomson scattering on ELMO Bumpy Torus

Journal Article · Wed May 01 04:00:00 EDT 1985 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1138523· OSTI ID:5639459

Cobble, J A

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), Journal Name: Rev. Sci. Instrum.; (United States) Vol. 56:5; ISSN RSINA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BUMPY TORI
DATA
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELMO BUMPY TORUS
ELMO DEVICES
EXPERIMENTAL DATA
INELASTIC SCATTERING
INFORMATION
LASER SPECTROSCOPY
LASERS
MAGNETIC MIRRORS
NUMERICAL DATA
OPEN PLASMA DEVICES
OPENINGS
OPERATION
PLASMA DIAGNOSTICS
RUBY LASERS
SCATTERING
SOLID STATE LASERS
SPECTROSCOPY
THERMONUCLEAR DEVICES
THOMSON SCATTERING
WINDOWS