Full Paper
Contents  Return  Previous Page  Next Page  Index

Return To: Session TH/P1 - Core Micro-instabilities and Transport
Prev Page: (TH/P1-03) Investigations of the Role of Nonlinear Couplings
Next Page: (TH/P1-06) Integral Equation Based Stability Analysis of Short

(TH/P1-04) Canonical Profiles in Tokamaks

Yu.N. Dnestrovskij1), S.E. Lysenko1, S.V. Cherkasov1
1) Nuclear Fusion Institute, RRC `Kurchatov Institute', Moscow, Russia

Abstract.  We consider the problem of the canonical profiles for tokamak plasma with arbitrary cross-section, taking into account two principles: 1) the free plasma energy minimum with the constraint of total current conservation and 2) the profile consistency. We deduce the Euler differential equation for the canonical profile of $ \mu$ = 1/q with two types of the boundary conditions: soft and stiff. The soft conditions correspond to the Kadomtsev solution for the circular cylinder. The stiff conditions describe a fast response of the plasma over the whole cross-section on the edge impact. Using the canonical profile of the current density, we calculate the critical gradients for the temperature, and create the transport model for the electron and ion temperatures and density. We show that, when the aspect ratio is diminished, or when the elongation increases, the canonical profiles become flatten. The similar tendency for the real profiles of the electron temperature was found in analyzis of JET and START experiments. The obtained critical gradients were used to analysis of the experiments in tokamaks with moderate and tight aspect ratios.

Read the full paper in PDF format.

IAEA 2003