Energy transfer of trapped electron turbulence in tokamak fusion plasmas

The first principle gyrokinetic simulations of trapped electron turbulence in tokamak fusion plasmas demonstrate the energy transfers from the most linearly unstable modes at high [Formula: see text] to intermediate [Formula: see text] via parametric decay process in a short period of linear-nonlinear transition phase. Dominant nonlinear wave-wave interactions occur near the mode rational surface [Formula: see text] . In fully nonlinear turbulence, inverse energy cascade occurs between a cutoff wave number [Formula: see text] and [Formula: see text] with a power law scaling [Formula: see text] , while modes with [Formula: see text] are suppressed. The numerical findings show fair agreement with both the weak turbulence theory and realistic experiments on Tore Supra tokamak.