Improved confinement in high density ohmic discharges in ASDEX
The unsaturated linear rise of the energy confinement time with density up to the density limit is recovered in Ohmically heated discharges in ASDEX. Improvement of a factor of 2 is reached with confinement time approximately 150ms at density about 5 x 1.0 E13/cm3. The improved state is characterised by peaked density profiles. The ion heat diffusivity decreases to the neoclassical value. The parameter ita(i) = L[n(e)]/L[T(i)], governing the onset of ion-temperature-gradient modes, falls to the stability threshold. The improvement in confinement might therefore be attributed to the stabilisation of ita(i) modes.
Bibliographic Reference: Article: Physical Review Letters, Vol. 61 (1988) No. 9, pp. 1105-1108
Record Number: 198911035 / Last updated on: 1994-12-01
Original language: en
Available languages: en