JET-P(92)76
High Bootstrap Current ICRH Plasmas in JET
High poloidal beta plasmas with a correspondingly high bootstrap fraction of 70%± 15% have been produced using ion cyclotron resonance heating. This high bootstrap fraction is achieved in an ELM free H-mode confinement regime. This regime is terminated by a large edge instability causing a reversion to L-mode confinement. Possible causes for this edge instability are discussed and the overall implications of these results for steady-state bootstrap dominated operation are examined.