Resurrection of crushed magnetization and chaotic dynamics in solution NMRspectroscopy

We show experimentally and theoretically that two readily observed effects in solution nuclear magnetic resonance (NMR)-radiation damping and the dipo lar field-combine to generate bizarre spin dynamics (including chaotic evol ution) even with extraordinarily simple sequences. For example, seemingly i nsignificant residual magnetization after a crusher gradient triggers expon ential regrowth of the magnetization, followed by aperiodic turbulent spin motion. The estimated Lyapunov exponent suggests the onset of spatial-tempo ral chaos and the existence of chaotic attractors. This effect Leads to hig hly irreproducible experimental decays that amplify minor nonuniformities s uch as temperature gradients. Imaging applications and consequences for oth er NMR studies are discussed.