At the American Physical Society Plasma Physics Conference in Long Beach, California in October 2001, a paper on the progress made on internal transport barrier plasmas in JET was presented. The main goal of advanced tokamak experiments is to obtain plasmas with fully non-inductive current, as opposed to the more standard inductive current plasmas where operation is restricted to a pulsed mode. The advanced tokamak scenario relies on a combination of self-generated plasma current (bootstrap current) and external current drive provided by additional heating systems.

In the EFDA-JET 2000-2001 experimental programme, one of the most interesting results was to observe the longest internal transport barriers, which have been produced in a tokamak so far. They went on for nearly 8s and corresponded to 27 times the energy confinement time, which is the time required for energy to leave the plasma. These discharges had more than 80% non-inductive current. Plasmas with full non-inductive current (1.8 MA) were maintained for a few seconds.

Real-time control experiments in this scenario have demonstrated that the local electron temperature gradient can be controlled with Ion Cyclotron Resonance Heating.

These new experiments allow the study of steady-state ITB plasmas in preparation of ITER operation.

Bootstrap current:
Self-generated current flowing in the plasma

Ion Cyclotron Resonance Heating
Additional heating method using radio-frequency waves at frequencies matching the frequency at which the ions gyrate around the magnetic field lines. The ICRH range of frequencies is 25–55 MHz.

Internal transport
barriers (ITB):
These barriers are insulating layers created in the plasma core that decreases the transport of particles and/or energy outside the plasma and gives rise to large pressure gradients.