SIGNATURES OF RESISTIVE BALLOONING MODES FOR ASDEX HIGH BETA-DISCHARGES

The signature of resistive ballooning modes in ASDEX high beta discharges are investigated. It is shown that the growth rates of these modes increase significantly when beta //p reaches its maximum value during the discharge and therefore they can be used to explain the 'hard beta //p saturation' behavior. A simple estimate of the corresponding electron heat conductivity gives values of chi //e greater than 1m**2 multiplied by s** minus **1, in agreement with expectations from the observed confinement deterioration at maximum beta.