Confinement properties of the 'advanced stellarator' Wendelstein W 7AS
Creators
- Renner, H.1
- Gasparino, U.1
- Maassberg, H.1
- Kuehner, G.1
- Ringler, H.1
- Sardei, F.1
- Weller, A.1
- Afanasiev, V.1
- Brakel, R.1
- Burhenn, R.1
- Cattanei, G.1
- Dodhy, A.1
- Dorst, D.1
- Elsner, A.1
- Engelhardt, K.1
- Erckmann, V.1
- Geissler, S.1
- Grieger, G.1
- Grigull, P.1
- Hacker, H.1
- Hartfuss, H.J.1
- Izvozchikov, A.1
- Jaenicke, R.1
- Jiang, S.1
- Junker, J.1
- Kick, M.1
- Kroiss, H.1
- Lakicevic, I.1
- Lazaros, A.1
- Mahn, C.1
- Ohlendorf, W.1
- Ochando, M.A.1
- Rau, F.1
- Saffert, J.1
- Sanchez, J.1
- Tutter, M.1
- Wuersching, E.1
- Zippe, M.1
- Zoepfel, S.1
- Zushi, H.1
- Penningsfeld, F.P.1
- Ott, W.1
- Speth, E.1
- Buechl, K.1
- Lang, R.1
- Kasparek, W.2
- Mueller, G.A.2
- Schueller, P.G.2
- Thumm, M.2
- W 7AS Team
- NBI Group
- Pellet Injection Group
- ECRH Team
- 1. Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.)
- 2. Stuttgart Univ. (Germany, F.R.). Inst. fuer Plasmaforschung
Description
An extended parameter range (Te ≤ 3 keV, Ti ≤ 0.7 keV, ne ≤ 2.5 1020 m-3) was explored in the new modular stellarator Wendelstein W 7 AS using ECRH and NBL. At 2.5 T main field central values of β up to 1.5% were achieved. A reduced Shafranov shift as consequence of the reduced Pfirsch-Schlueter currents for the advanced stellarator concept is verified. Depending on the plasma parameters a net current is observed and identified as the bootstrap current. At the low shear stellarator W 7 AS the magnetic configuration and the confinement depends sensitively on the plasma currents. Thus a control of the configuration by small currents (OH, ECCD, Ohkawa curent) is applied to maintain optimum confinement. Based on profile measurements the electron heat conduction and the ion particle diffusion coefficient were evaluated for ECRH plasmas. As result of statistical analysis a phenomenological expression for the energy confinement time τE is derived. After carbonization the high Z impurities (Fe, Ti) and radiation losses were significantly reduced. At first experiments with NBI (PIN ≤ 1.5 MW) discharges at density ne ≤ 2.5 1020 m-3 could be maintained and an energy replacement time of up to 30 ms was achieved. (orig.)
Additional details
Publishing Information
- Imprint Title
- W7AS contributions 1990 to 13th international conference on plasma physics and controlled nuclear fusion research in Washington, October 1-6, 1990; 17th EPS conference on controlled fusion and plasma heating in Amsterdam, June 25-29, 1990; 9th international conference on plasma surface interaction in controlled fusion devices in Bournemouth, May 28-30, 1990
- Imprint Pagination
- 76 p.
- Journal Page Range
- p. 1-14.
- Report number
- IPP--III/172
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 22070281
- Subject category
- S70: PLASMA PHYSICS AND FUSION TECHNOLOGY; S70: PLASMA PHYSICS AND FUSION TECHNOLOGY;
- Descriptors DEI
- BEAM INJECTION HEATING; BETA RATIO; BOOTSTRAP CURRENT; CARBONIZATION; CONFINEMENT TIME; DIFFUSION; ECR HEATING; ELECTRIC CURRENTS; ELECTRON DENSITY; ELECTRON TEMPERATURE; ICR HEATING; IMPURITIES; IRON; MAGNETIC CONFINEMENT; NEUTRAL ATOM BEAM INJECTION; PFIRSCH-SCHLUETER REGIME; ROTATIONAL TRANSFORM; SPATIAL DISTRIBUTION; THERMAL CONDUCTION; TITANIUM; WENDELSTEIN-7 STELLARATOR
- Descriptors DEC
- BEAM INJECTION; CHEMICAL REACTIONS; CLOSED PLASMA DEVICES; CONFINEMENT; CURRENTS; DECOMPOSITION; DISTRIBUTION; ELEMENTS; ENERGY TRANSFER; HEAT TRANSFER; HEATING; HIGH-FREQUENCY HEATING; METALS; PLASMA CONFINEMENT; PLASMA HEATING; STELLARATORS; THERMONUCLEAR DEVICES; TRANSITION ELEMENTS
Optional Information
- Collaborations
- W 7AS Team; NBI Group; Pellet Injection Group; ECRH Team.