Ion cyclotron resonance heating in the divertor tokamak ASDEX

Journal Article · Thu May 01 04:00:00 EDT 1986 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.573414· OSTI ID:5653961

Steinmetz, K; Wesner, F; Niedermeyer, H; Becker, G; Braun, F; Eberhagen, A; Fussmann, G; Gehre, O; Gernhardt, J; v Gierke, G

The main topics of ICRF investigations in ASDEX are the influence of the divertor on impurity production and transport in ICRH heated discharges, and the heating efficiency and plasma confinement in various scenarios (minority and harmonics regimes). The first experiments were conducted in November 1984 at 67 MHz, corresponding to second harmonic heating of a hydrogen plasma at B/sub 0/ = 2.2 T. A transmitted power of 2.5 MW has been reached so far, the total capability being 3 MW. A linear increase of the central electron and ion temperature with the rf power is observed in Ohmically preheated plasmas (..delta..T/sub e/approx.280 eV, ..delta..T/sub i/approx.500 eV, ..delta..W/sub p/approx.17 kJ at a power of 1.2 MW coupled to the plasma and n-bar/sub e/ = 3.5 x 10/sup 13/ cm/sup -3/). The total radiation increases linearly with the power, too, and the ratio P/sub rad//P/sub tot/approx.0.35 stays approximately constant. However, first investigations indicate that with a divertor, ICRF operation is also accompanied by a significant increase in impurity production. The presence of neutral beam injection in addition to ICRH clearly enhances the absorption of the wave energy from about 50% to up to 90% with respect to the coupled power. With neutral beam injection (P/sub NI/< or =3.5 MW) the increment of the plasma energy content due to ICRH (P/sub rf/< or =2 MW) is found to be almost twice as large as in case OH+ICRH. Global heating efficiencies of up to 3 x 10/sup 13/ eV/kW cm/sup 3/ compare quite well with other ICRH experiments. First observations indicate a degradation of plasma confinement with ICRH to values in between L-type and OH confinement.

• Research Organization: Max-Planck-Institut fuer Plasmaphysik, Euratom Association, D-8046 Garching, Federal Republic of Germany
• OSTI ID: 5653961
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 4:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700205* -- Fusion Power Plant Technology-- Fuel
Heating
&amp; Injection Systems
ASDEX TOKAMAK
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
CONFINEMENT
DIVERTORS
EFFICIENCY
ELECTRON TEMPERATURE
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
IMPURITIES
ION TEMPERATURE
OPERATION
PLASMA CONFINEMENT
PLASMA HEATING
POWER
RADIATION TRANSPORT
THERMONUCLEAR DEVICES
TOKAMAK DEVICES