JET Joint Undertaking Progress Report 1991 (Volume II)Funded under: FP2-FUSION 10C
During its 1990 operation, 2 large RF systems were available on JET. The ion cyclotron resonance heating (ICRH) system was equipped with new beryllium screens and with feedback matching systems. Specific impurities generated by ICRH were reduced to negligible levels even in the most stringent H-mode conditions. A record power of 22 MW was coupled to the plasma. High quality H-modes with tau(E) greater than or equal to 2.5 tau(EG) were achieved using dipole phasing. A new high confinement mode was discovered. It combines the properties of the H-mode regime with the low central diffusivities obtained by pellet injection. A value of n(d)tau(E)T(i) = 7.8 x 1.0E20/m3 s keV was obtained in this mode with both T(e) and T(i) approximately equal to 11 keV. In the L-mode regime, a record (140kW) D-3He fusion power was generated with 10-14 MW of ICRH at the 3He cyclotron frequency. Experiments were performed with the prototype launcher of the lower hybrid current drive (LHCD) systems with coupled power up to 1.6 MW with current drive efficiencies up to 0.4 x 1.0E20/m2 A/W. Fast electrons are driven by LHCD to tail temperatures of 100 keV with a hollow radial profile. Paradoxically, LHCD induces central heating particularly in combination with ICRH. Finally, the first observations of the synergistic acceleration of fast electrons by transit time magnetic pumping (TTMP) (from ICRH) and electron Landau damping (ELD) (from LHCD) are presented. The synergism generates TTMP current drive even without phasing the ICRH antennae.
Bibliographic Reference: EUR 14434 EN (1992) 314 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199210888 / Last updated on: 1994-12-02
Original language: en
Available languages: en