Sub-grid-scale effects in magnetised plasma turbulence

In the present paper, we use a coarse-graining approach to investigate nonlinear redistribution of free energy in both position and scale space for weakly collisional magnetised plasma turbulence. For this purpose, high-resolution numerical simulations gyrokinetic (GK) turbulence that span proton-electron range scales, straight magnetic guide field geometry. Accounting averaged effect particles' fast gyro-motion on slow fluctuations, GK approximation captures dominant mechanisms strongly Here, system is coarse-grained with respect cut-off scale, separating real contributions interactions from coarse-grid-scales sub-grid-scales (SGS). We concentrate analysis SGS effects. Not only allows us flux across but also now analyse its spatial density. find net value an order magnitude smaller than positive negative density contributions. The dependence results filter type analysed. Moreover, advection space. This rather novel can help development models account advective unstable structures fusion plasmas, turbulent transport saturation.