Chaos suppression by feedback control in nuclear magnetic resonance

The strength of static magnetic field and the sensitivity of probe increase with the technique development of modern nuclear magnetic resonance (NMR) spectrometer. Radiation damping effect thus can no longer be neglected in solution NMR experiments with abundant spins. The cooperative effects of radiation damping and distant dipolar field (DDF) generate spin turbulence, which makes the evolution of magnetization unpredictable by traditional NMR theory and causes the uncertainty of acquired signals. The chaos phenomena can be described by introducing a radiation damping term into the Bloch equations. In this paper, we used two kinds of feedback control method to suppress the chaotic process. Numerical simulation indicates their feasibility and efficiency.