Blowout Bifurcations and the Onset of Magnetic Activity in Turbulent Dynamos

The transition to magnetic-field self-generation in a turbulent, electrically conducting fluid is shown to exhibit intermittent bursting characterized by distinct scaling laws. This behavior is predicted on the basis of prior analysis of a type of bifurcation (called a blowout bifurcation) occurring in chaotic systems with an invariant phase space submanifold. The predicted scalings are shown to be consistent with numerical solutions of the governing magnetohydrodynamic equations, and implications for recently implemented experimental programs are discussed.