Entropy-induced chaos in magnetized plasma: Insights from nonlinear dynamics

Abstract

This research introduces a novel theoretical investigation into the fundamental influence of entropy on plasma dynamics, particularly its role in governing confinement and transport phenomena within magnetically confined thermonuclear fusion systems. Utilizing Braginskii's transport formalism alongside a drift approximation to incorporate entropy-driven effects, a new class of nonlinear evolution equations is derived. These equations expose previously unrecognized couplings between entropy variations and ion temperature gradient (ITG) modes. A thorough examination of the linear dispersion relation elucidates key features of wave propagation, while nonlinear analysis reveals entropy-induced transitions to chaotic behavior, reminiscent of the Lorenz-Stenflo model, a well-known representation of turbulence in plasma. This study redefines entropy as an active agent in the emergence of instability and turbulence, rather than merely a passive thermodynamic variable. The findings offer critical insights into enhancing plasma confinement and stability, potentially advancing the realization of efficient and sustainable nuclear fusion.