Flux of metal impurities from the antenna during rf plasma production and heating in the Uragan-3 torsatron

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Sov. J. Plasma Phys. (Engl. Transl.); (United States)

OSTI ID:6932526

Voitsenya, V S; Dikii, A G; Konovalov, V G; Nazarov, N I; Pavlichenko, O S; Polyakova, G N; Remez, L N; Rubtsov, K S; Shapoval, A N; Shvets, O M; others, and

The flux of metal impurities (chromium and iron) near the rf antenna has been studied in the Uragan-3 torsatron. The heating was carried out in the ion-cyclotron-resonance frequency region. Experiments were carried out with a hydrogen plasma with a power injection of 200 kW, H/sub 0/ = 4.8 kOe, n-bar/sub e/ = 7.5x10/sup 12/ cm/sup -3/, and T/sub i//similar to/00 eV. The electron temperature T/sub e/ varied from 100 to 300 eV over the course of the pulse, which was 3 ms long. Spectroscopic studies of the spatial distributions of the intensity of the emission in CrI and TiI lines showed that the source of the metal impurities in this experient was the rf antenna. A study of the velocity distribution of chromium atoms led to the identification of the primary mechanism for the erosion of the antenna surface. These velocity distributions corresponded to a velocity (2.5--3)x10/sup 6/ cm/s at the maximum of the distribution function. This figure is well above the velocity of sputtered atoms (/similar to/x10/sup 5/ cm/s) and agrees with the typical velocities of the particles during arcing. The densities of chromium and iron atoms near the antenna were measured. The flux of these atoms into the plasma was estimated, with allowance for the attenuation in the ergodic magnetic field around the confinement volume. The relative density of metal impurities in the plasma turns out to be 1% if it is assumed that all the metal atoms from the antenna which pass through the confinement ergodic layer are ionized and accumulate in the volume.

• Research Organization: Physicotechnical Institute, Academy of Sciences of the Ukrainian SSR, Khar'kov
• OSTI ID: 6932526
• Journal Information: Sov. J. Plasma Phys. (Engl. Transl.); (United States), Vol. 14:6
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
URAGAN STELLARATOR
ICR HEATING
IMPURITIES
ANTENNAS
CHROMIUM
DIVERTORS
SPUTTERING
TITANIUM
CLOSED PLASMA DEVICES
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
HEATING
HIGH-FREQUENCY HEATING
METALS
PLASMA HEATING
STELLARATORS
THERMONUCLEAR DEVICES
TRANSITION ELEMENTS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production