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The future JET (Joint European Torus) program will be mainly focused on the consolidation of the physics basis of the main ITER scenarios. This gives a strong motivation for examining the feasibility of the construction and implementation of an ECRH (Electron Cyclotron Resonance Heating) system in JET for an intensive exploitation before the start of ITER. To advance this feasibility study towards the approval of the project, collaboration between the E4J (ECRH for JET) project team and the KIT (Karlsruhe Institute of Technology) design team of the ITER ECH Port Plug was decided. The aim of this collaboration was to raise the principal design requirements and to establish a rough design of the main components of an E4J system.

For heating and current drive experiments by electron cyclotron resonance interaction on the Tore Supra Tokamak, an ECRH system with a generator power of 2.4 MW (3 MW) for a pulse duration of 210 s (5 s) at a frequency of 118 GHz is presently under construction at CEA Cadarache. The generator is made of six TH 1506B gyrotrons. The main design parameters of the gyrotron are given in this paper. Prototype and first series gyrotrons are already installed on Tore Supra.

The ECRH experiment on TORE SUPRA is designed to inject up to 3 MW of power at 118 GHz, using an antenna consisting of six fixed spherical mirrors and three mobile steering minors. The position of the mobile mirrors can be varied in real time using two stepper motors for each mobile mirror. In addition to controlling the injection angle, the position of the mobile mirrors also affects the polarisation of the injected wave. Accurate formulae to computer in real time, the stepper motor positions required to obtain the desired beam injection angles have been derived. Formulae to determine the effect on the wave polarisation, of the actual mobile mirror positions have also been determined. These formulae have been verified by precise laser measurements and by comparison of power deposition calculations and experimental results. Experiments with different values of polarisation and injection angles have been carried out in the 2001 campaign.

Recently a local criterion characterising the emergence and space-time evolution of internal transport barriers (ITB) has been proposed and extensively validated on the large JET database. It was shown that a dimensionless local parameter, /spl rho//spl dot/(T/sub e/) =/spl rho//sub s//L(T/sub e/) characterises with a low computational cost the typical ITB features such as the emergence time, location, collapse time and dynamics [/spl rho//sub s/ is the local Larmor radius and L(T/sub e/) is the temperature gradient scale length L(T/sub e/)=-T/sub e//(/spl part/T/sub e///spl part/R)]. We report on the recent implementation of the calculation of the ITB criterion together with the associated feedback algorithms in the real time system of JET. The system purpose is to acquire all the analogue channels of the high space resolution electron temperature ECE diagnostic (heterodyne radiometer) and to calculate in real time the relevant ITB parameters which am used for the control: the maximum value of the dimensionless local temperature gradient, the ITB radius and width, the core and volume averaged electron temperature.

Summary form only given. A system working at the electron cyclotron resonance frequency is under construction at CEA Cadarache for heating and current drive experiments in the thermonuclear controlled fusion field of research. This system will be able to couple 3 MW with a 5 s pulse length or 2.4 MW for up to 600 s into the plasma of the Tore Supra Tokamak at the resonant electron cyclotron frequency of 118 GHZ.

The Lower Hybrid Current Drive (LHCD) system has been in operation since 1994. Its power handling capability and its operation have been increased by improvements and installation of feedback controls on klystron power, launcher position, plasma position, plasma internal inductance, loop voltage and gas introduction. The power is applied during the plasma formation and the current ramp-up, providing a target current profile favourable for high neutron rate performance in shear optimisation experiments. To further the design of a launcher for an ITER relevant system, high and low power tests have been carried out on a module allowing the transmission of a TE/sub 3.0/ mode.