Turbulence and the nonlinear dynamics of sawteeth in tokamaks
This paper presents the development of a nonlinear dynamical model for the temporal behaviour of sawteeth. A full set of conservation equations and constitutive relations applying to the turbulent transport of energy and particles is considered, and a formal invariance principle relating to the structure of turbulent correlations is formulated. The model provides a theory for the temporal aspects of the complete sawtooth cycle including expressions for the sawtooth period, amplitude and crash times in terms of the specified sawtooth-averaged plasma equilibrium and transport properties. Comparisons are made with data from TEXT, JET and TEXTOR which operate under different conditions. The model accounts for the observed features of all three machines and leads to scaling laws between period, amplitude and crash times.
Bibliographic Reference: Report: UKAEA FUS 275 EN (1994) 30 pp.
Availability: Available from the Librarian, UKAEA, Culham Laboratory, Abingdon, Oxon. OX14 3DB (GB)
Record Number: 199510077 / Last updated on: 1995-01-10
Original language: en
Available languages: en