Thermal electron transport in regimes with low and negative magnetic shear in Tore Supra
The magnetic shear effect on thermal electron transport is studied in a large variety of non-inductive plasmas in Tore Supra. An improved confinement in the region of low and negative shear was observed and quantified with an exponential dependence on the magnetic shear. This is interpreted as a consequence of a decoupling of the global modes that are thought to be responsible for anomalous transport. This dependence is proposed in order to complete the Bohm-like L-mode local electron thermal diffusivity so as to describe the transition from Bohm-like to gyroBohm transport in the plasma core. The good agreement between the predictive simulations of the different Tore Supra regimes (hot core lower hybrid enhanced performance, reversed shear plasmas and combined lower hybrid current drive and fast wave electron heating) and experimental data provides a basis for extrapolation of this magnetic shear dependence in the local transport coefficients to future machines. As an example, a scenario for non-inductive current profile optimization and control in the international thermonuclear experimental reactor (ITER) is presented.
Bibliographic Reference: Article: Nuclear Fusion, Vol.37 (1997) No. 12, pp. 1715-1733
Record Number: 199810183 / Last updated on: 1998-02-12
Original language: en
Available languages: en