JET RECENT RESULTS ON WAVE HEATING AND CURRENT DRIVE CONSEQUENCES FOR FUTURE DEVICES

The latest developments of the JET ICRH and LHCD systems are reviewed. Feedback controls have alleviated the traditional difficulties with plasma-antenna coupling. Experimental results on high plasma performance, basic confinement aspects and issues relevant to the next generation of tokamaks are described. ICRH allows a narrow power depositon profile to be localised at will independently of the plasma density and size. We demonstrate that in large tokamaks, the constraint to use a minority species can be removed and heating a balanced D/T mixture at omega = omega(CD) in ITER is proposed. LHCD allows the highest current drive efficiency to be obtained. The conditions for wave accessibility are discussed in light of the JET results. LHCD is well adapted to save volt seconds in the current rise phase. The observed synergistic LHCD/ICRH acceleration of fast electrons is a promising route towards higher current drive efficiency but raises unresolved physics aspects which are analysed. We finally consider the prospects of a steady state fusion reactor.