Thomson scattering on ELMO Bumpy Torus

Technical Report · Mon Apr 01 04:00:00 EST 1985

DOI:https://doi.org/10.2172/5883420· OSTI ID:5883420

Cobble, J. A.

Below 10/sup 12/ cm/sup -3/ density, a Thomson scattering experiment is an exacting task. Aside from the low signal level, the core plasma in this instance is bathed in high-energy x rays, surrounded by a glowing molecular surface plasma, and heated steady state by microwaves. This means that the noise level from radiation is high and the environment is extremely harsh-so harsh that much effort is required to overcome system damage. In spite of this, the ELMO Bumpy Torus (EBT) system has proven itself capable of providing reliable n/sub e/ and T/sub e/ measurements at densities as low as 2 x 10/sup 11/ cm/sup -3/. Radial scans across 20 cm of the plasma diameter have been obtained on a routine basis, and the resulting information has been a great help in understanding confinement in the EBT plasma. The bulk electron properties are revealed as flat profiles of n/sub e/ and T/sub e/, with density ranging from 0.5 to 2.0 x 10/sup 12/ cm/sup -3/ and temperature decreasing from 100 to 20 eV as pressure in the discharge is increased at constant power. Evidence is presented for a suprathermal tail, which amounts to about 10% of the electron distribution at low pressures. The validity of this conclusion is supported by two independent sensitivity calibrations.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5883420
• Report Number(s): ORNL/TM-9471; ON: DE85010584
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BUMPY TORI
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELMO BUMPY TORUS
ELMO DEVICES
INELASTIC SCATTERING
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PERFORMANCE
PLASMA DIAGNOSTICS
SCATTERING
THERMONUCLEAR DEVICES
THOMSON SCATTERING