Stationary magnetic shear reversal during lower hybrid experiments in Tore Supra
Stable and stationary states with hollow current density profiles have been achieved with Lower Hybrid Current Drive (LHCD) during Lower Hybrid (LH) wave accessibility experiments. By analysing the bounded propagation domain in phase space which naturally limits the central penetration and absorption of the waves, off-axis LH power deposition has been realized in a reproducible manner. The resulting current density profile modifications have led to a global confinement enhancement attributed to the formation of an internal transport barrier in the central reversed shear region where the electron thermal diffusivity is reduced to its neoclassical collisional level. The multiple-pass LH wave propagation in the weak Landau damping and reversed magnetic shear regime is also investigated in the framework of a statistical theory [K. Kupfer, et al Phys. Fluids B, 5 (1993) 4391] and the experimental validation of this theory is discussed.
Bibliographic Reference: Report: 1565 EN (1996) 26pp.
Availability: Available from Association Euratom-CEA, CEN Cadarache, 13108 Saint-Paul-lez-Durance (FR)
Record Number: 199610655 / Last updated on: 1996-06-10
Original language: en
Available languages: en