Extreme heat fluxes in gyrokinetic simulations: A new critical \beta
M. J. Pueschel, P. W. Terry, F. Jenko, D. R. Hatch, W. M. Nevins, T. Görler, and D. Told
Accepted
A hitherto unexplained feature of electromagnetic simulations of ion temperature gradient turbulence is the apparent failure of the transport levels to saturate for certain parameters; this effect, termed here Non-Zonal Transition, has been referred to as the high-b runaway. The resulting large heat fluxes are shown to be a consequence of reduced zonal flow activity, brought on by magnetic field perturbations shorting out flux surfaces.