Details

Autor(en) / Beteiligte

• Hahm, T. S.
• Diamond, P. H.
• Terry, P. W.
• Garcia, L.
• Carreras, B. A.

Titel

Role of impurity dynamics in resistivity‐gradient‐driven turbulence and tokamak edge plasma phenomena

Ist Teil von

• The Physics of fluids (1958), 1987-05, Vol.30 (5), p.1452-1465

Ort / Verlag

Woodbury, NY: American Institute of Physics

Erscheinungsjahr

1987

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The role of impurity dynamics in resistivity‐gradient‐driven turbulence is investigated in the context of modeling tokamak edge plasma phenomena. The effects of impurity concentration fluctuations and gradients on the linear behavior of rippling instabilities and on the nonlinear evolution and saturation of resistivity‐gradient‐driven turbulence are studied both analytically and computationally. At saturation, fluctuation levels and particle and thermal diffusivities are calculated. In particular, the mean‐square turbulent radial velocity is given by 〈v̂2 r 〉 =(E 0 L s /B z )2 (L −1 η+L −1 z )2. Thus edged peaked impurity concentrations tend to enhance the turbulence, while axially peaked concentrations tend to quench it. The theoretical predictions are in semiquantitative agreement with experimental results from the TEXT [Bull. Am. Phys. Soc. 3 0, 1443 (1985)], Caltech [Phys. Fluids 2 9, 309 (1986)], and Tosca [in the P r o c e e d i n g s o f t h e 1 2 t h E u r o p e a n C o n f e r e n c e o n C o n t r o l l e d F u s i o n a n d P l a s m a P h y s i c s (European Physical Society, Budapest, 1985), Vol. I, p. 311] tokamaks. Finally, a theory of the density clamp observed during CO‐NBI on the ISX‐B tokamak [in P l a s m a P h y s i c s a n d C o n t r o l l e d N u c l e a r F u s i o n R e s e a r c h (IAEA, Vienna, 1981), Vol. I, p. 377] is proposed.