The power dependence of the maximum achievable H-Mode and (disruptive) L-Mode separatrix density in ASDEX Upgrade

In future fusion reactors disruptions must be avoided at all costs. Disruptions due to the density limit are typically described by the power-independent Greenwald scaling. Recently, a power dependence of the disruptive density limit was predicted by several authors. It is investigated whether this increases the operational range of the tokamak. Increasing the heating power in the L-mode can induce an L-H transition, and therefore a power-dependent density limit and the L-H transition cannot be considered independently. The different models are tested on a data base for separatrix parameters at the separatrix of ASDEX Upgrade and compared with the concept (SepOS) presented in T.Eich, P. Manz Nuclear Fusion 61 (2021) 086017. For future devices operating at much higher heating power such a power scaling may allow operation at much higher separatrix densities as common in H-Mode operation. Preconditions to extrapolation for future devices are discussed.