GCST-based Stability Control in Fusion Plasmas A Conceptual Framework for Dynamic Suppression of Turbulence and Rate-Induced Instabilities

Abstract Fusion plasmas are strongly driven, nonlinear systems where rate-induced instabilities dominate transport and confinement degradation. Global Complexity Stability Theory (GCST) provides a unified description through the evolution equation of the instability field Ψ: ∂Ψ/∂t = D ∇² Ψ + C α − γ Ψ We introduce the GCST-Plasma Number G_plasma = γ / (α C), an inverse stability metric analogous to a turbulent Reynolds number. When G_plasma < 1, instability debt accumulates, leading to enhanced transport and mode coupling. The ARC-Fusion approach shifts the control paradigm from passive high-field confinement to active, feedback-driven maximization of γ_eff via real-time modulation of magnetic topology, heating profiles, and zonal-flow excitation. Numerical simulations demonstrate rate-induced transitions and the role of recovery rate γ in suppressing turbulence growth.