Effects of ballooning instability on tokamak confinement

Using the ballooning-mode transport model proposed by Connor, Taylor & Turner (1984), we derive the thermal conductivity induced by ideal ballooning instability and compare it to experimental observations from auxiliary-heated tokamaks. We show how this model can be improved by means of a finite-beta equilibrium and also apply it to obtain a confinement scaling law for high-beta, purely Ohmically heated tokamaks. Finally, we employ this transport mode to find that tokamaks with supplemental stabilization, for example due to gyroradius, energetic particle or shaping effects, can self-consistently access the second stability regime at rather high heating power.