Growth rates of ITG modes in the presence of flow shear

Plasma microinstabilities in toroidal magnetic confinement devices can be driven unstable by a radial ion temperature gradient and stabilized by rotational flow shear. In this study, we argue that these nonlinear dynamics can be captured by the linear stabilization of Floquet modes. To that end, we propose a novel method (the τAC method) to calculate growth rates by averaging over linear Floquet modes. The τAC method is compared to nonlinear and other linear approaches and is shown to work well at low parallel velocity gradient drive. As such, the method provides a promising approach to explore the parameter dependencies of flow shear stabilization.