The scaling of the edge electron temperature at the L-H transition based on the Alfvén drift-wave instability
The stability theory of Alfvén drift-waves shows that with increasing plasma pressure the Alfvén waves get coupled to electron drift waves. This instability can be characterised by 2 significant parameters, ie the normalised plasma beta and the normalised collision frequency. The resulting turbulent transport coefficient is suppressed when the normalised beta is greater than a critical value, which depends on the normalised collision frequency, nu(n). The transport coefficients change their dependence on plasma parameters at this threshold. The Alfvén drift-wave model predicts the scaling of the electron edge temperature at the L-H transition with respect to the toroidal field, plasma current, density and other plasma parameters. The experimental data corresponding to the L-H transition on different tokamaks exhibit a similar behaviour in the T(0)- n(0) diagram, in particular a weak dependence of T(0) on the density at high densities but a more pronounced increase at low densities.
Bibliographic Reference: Report: JET-P(98)01 EN (1998) 28pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199810525 / Last updated on: 1998-05-05
Original language: en
Available languages: en