High poloidal beta plasmas with a correspondingly high bootstrap fract
ion of 70 +/- 15% have been produced using ion cyclotron resonance hea
ting, in an ELM free H mode confinement regime. This regime is termina
ted by a large edge instability, causing a reversion to L mode confine
ment. Possible causes for this instability am discussed and the overal
l implications of the results for steady state bootstrap dominated ope
ration are examined.