Turbulent structures shape in 3D global simulations of edge plasma turbulence with divertor geometry

摘要

1 Objectives of the work and simulations setup The TOKAM3X code allows to simulate tokamak plasma edge turbulence in divertor geometry [1], including both open and closed flux surfaces. We focus here on the effects of divertor geometry on edge turbulent structures shape, performing global flux-driven simulations. Turbulent structures are generated self-consistently in the edge region, as a result of the interchange mechanism, and propagate radially, until they are dissipated in the Scrape-Off Layer (SOL) under the action of the boundary conditions at the sheath. With this first-principle approach, we evaluate the deformation of turbulent structures in the 3D space. The physical model solved by TOKAM3X is described in [1]. It is a drift-reduced, electrostatic turbulence model, and it is used at present in its isothermal version, without the description of neutral dynamics. The parameters of the model are set as in [2]. A COMPASS-like diverted geometry is used: a poloidal cross section showing density fluctuations at a specific time step is represented in figure la. The actual value of the poloidal field can be rescaled in order to obtain a realistic safety factor, whose profile is represented in figure lb.