Improved confinement with peaked density profiles caused by T(e) profile invariance
The origin of the better energy and particle transport with peaked density profiles observed in ohmic plasmas and auxiliary heated plasmas is investigated. It is found that this property results from a reduction of the non-local component of the electron heat diffusivity X(e) caused by T(e) profile invariance in the outer half of the plasma. Density profile peaking diminishes the net electron heating power and the conductive electron heat flux, which forces X(e) to adjust in such a way that the T(e) profile shape is conserved. Owing to the coupling with X(e), the diffusion coefficient D is also reduced, which improves the particle confinement time and leads to the density profile peaking.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 31 (1991) No. 7, pp. 1243-1248
Record Number: 199111169 / Last updated on: 1994-12-02
Original language: en
Available languages: en