Non-Ballooning Electron Temperature Gradient Turbulence in the Tokamak Pedestal*

Tokamak pedestal electron temperature gradient (ETG) turbulence has a complex three-dimensional structure that is highly inhomogeneous in the poloidal direction, particularly at ion scales. Nonlinear multiscale gyrokinetic simulations of Joint European Torus pedestals reveal that ETG pedestal turbulence has maximum fluctuation amplitudes and transport near the top and bottom of a flux surface, rather than the outboard midplane. Its parallel distribution is determined by the magnetic field geometry and steep equilibrium gradients, with magnetic drift and finite Larmor radius effects being particularly important. Nonlinear simulations must run sufficiently long for the slower ion-scale ETG turbulence to saturate and interact with electron-scale ETG turbulence.