Application of Mutual Information Methods in Time–Distance Helioseismology
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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.
KeywordsHelioseismology, observations Helioseismology, theory Velocity fields, interior
NSO is operated by the Association of Universities for Research in Astronomy (AURA, Inc.), under a cooperative agreement with the National Science Foundation (NSF). The SOHO/MDI data used here are provided by the SOHO/MDI consortium. SOHO is a project of international cooperation between ESA and NASA. The authors thank the anonymous referee for his/her suggestions that allowed the authors to improve the article.
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