Scale separation between electron and ion thermal transport.

Nonlinear gyrokinetic simulations of microturbulence simultaneously driven by electron temperature gradient modes, trapped electron modes, and ion temperature gradient modes are presented, covering both electron and ion spatiotemporal scales self-consistently. It is found that, for realistic ion heat (and particle) flux levels and in the presence of unstable electron temperature gradient modes, there tends to be a scale separation between electron and ion thermal transport. In contrast to the latter, the former may exhibit substantial or even dominant high-wave-number contributions.