Application of Mutual Information Methods in Time-Distance Helioseismology

We apply a new technique, the mutual information (MI) from information theory, to time-distance helioseismology, and demonstrate that it can successfully reproduce several classic results based on the widely used cross-covariance method. MI quantifies the deviation of two random variables from complete independence and represents a more general method for detecting dependencies in time series than the cross-covariance function, which only detects linear relationships. We briefly describe the MI-based technique and discuss the results of applying MI to derive the solar differential profile, a travel-time deviation map for a sunspot, and a time-distance diagram from quiet-Sun measurements.