Tore Supra results on stochastic edge layers
On Tore Supra (R = 2.4 m, a = 0.76 m, I(p) = 1 - 2 MA, B(T) = 3 - 4.5 T) six in-vessel coils create a radial magnetic perturbation such that the value of delta B/B is approximately 1.0 E-3. The spectrum of this perturbation is designed so that the edge layer is stochastic over small density changes of about 20 %. In this soft separatrix the transport is modified which allows, to some extent, control of the edge parameters. The main experimental results are a reduction of the plasma edge temperature, a screening of the particle influx (D and impurities both intrinsic and extrinsic) and a stabilisation of the (2,1) MHD mode. While the effect on the electron transport (temperature and current profile) is readily predicted, the change in particle transport is not fully understood. Experimental evidence on the role of ionisation lengths, edge temperature and wall pumping properties is cited. The code Mastoc is used to model the deposition pattern of both the heat and particle fluxes where the effect of finite connexion length prevails. Smooth and well localised plasma wall interaction domains are predicted in agreement with the experimental results.
Bibliographic Reference: Paper presented: 34th APS Division of Plasma Physics, Seattle (US), November 16-20, 1992
Availability: Text not available
Record Number: 199310053 / Last updated on: 1994-11-29
Original language: en
Available languages: en