Dimensional analysis of empirical electron heat diffusivities and comparison with microturbulence induced transport
Empirical scaling laws for the electron heat diffusivity x(e) in the OH, L and H regimes are expressed in dimensionless form. It is found that particle orbit, collisionality and finite beta effects enter in all regimes. The different scalings are shown to result from changes in the finite ß contribution, i.e. in magnetic turbulence induced transport. A unified scaling law is presented which also holds for the intermediate region between OH and L confinement. Purely electrostatic drift wave models including gyrokinetic effects and collisions yield B(t), A(i) and T(e) scalings incompatible with the empirical results. Inclusion of electromagnetic effects and pressure-driven terms, e.g. due to resistive ballooning modes, is shown to be necessary.
Bibliographic Reference: Report: IPP III/146 EN (1989)
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
Record Number: 198911000 / Last updated on: 1994-12-01
Original language: en
Available languages: en