Evolution of Internal Transport Barriers in JET Optimized Shear Plasmas
High performance discharges with optimized magnetic shear having a broad or hollow current density profile have been produced in JET. These plasmas are characterized by improved core confinement within a region called the Internal Transport Barrier. Near the plasma centre, the ion thermal diffusivity is reduced to levels close to the standard neo-classical level in both D-D and D-T plasmas. With D-D fuel, a JET record neutron yield was produced and, with D-T fuel, L-mode discharges with 7.2 MW of fusion power, and H-mode discharges with up to 8.2MW of fusion power are obtained. Central ion temperatures approaching 40 KeV, ion temperature gradients of 150 KeVm(-1) and plasma pressure gradients of 10(6)Pa m(-1) are observed in D-T leading to a fusion triple product. Central toroidal rotation frequencies up to 37 kHz are observed and rotational flow near the radius of the ITB is strongly sheared.
Bibliographic Reference: Article: JET-P(98)68
Record Number: 199910831 / Last updated on: 1999-06-11
Original language: en
Available languages: en