Solar Physics
Aim of the project
The project in solar physics is an interdisciplinary scientific collaboration between helioseismology and time series analysis.
The main issue of our research in helioseismology is the detection and quantification of mode couplings from observations of solar oscillations. For this purpose, we investigate methods from linear and non-linear multivariate time series analysis, like cross-spectral analysis, partial directed coherence and higher order spectral analysis. These methods enable the detection and quantification of direction and strength of couplings between stochastic processes. Our work is motivated by several publications, especially
M. Winterhalder, B. Schelter, J. Timmer
Detecting coupling directions in multivariate oscillatory systems. Int. J. Bif. Chaos (2007)
B. Schelter, M. Peifer, M. Winterhalder, J. Timmer Testing for phase synchronization. Phys. Lett. A 366 (2007)
M. Roth, M. Stix Coupling of solar p modes: quasi-degenerate perturbation theory. Astron. Astrophys. 351, 1133-1138 (1999)
M. Roth Anti-Correlated Coupling p-Modes. Astroph. Journal, 559, 1165 (2001)
M. Roth, M. Stix Time-Dependent Coupling of Solar Oscillations. Astron. Astrophys., 405, 779-786 (2003)
The group
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Prof. Dr. Jens Timmer (Freiburg Center for Data Analysis and Modeling, Freiburg, Germany)
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Dipl. Phys. Ariane Schad (Freiburg Center for Data Analysis and Modeling, Freiburg, Germany)
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Dr. Markus Roth (KIS, Freiburg, Germany)
Publications
Schad A., Timmer J., Roth M. A unified approach to the helioseismic inversion problem of the solar meridional flow from global oscillations. Astrophys. J. 734, 97, 2011
Schad A., Roth M., v. d. Lühe O., Timmer J. Cross-spectral analysis of solar oscillation time series. Proc. HELAS-II Int. Conf., J. Phys. Conf. Ser., 118, 2008 pdf
This project is in cooperation with the Kiepenheuer-Institut für Sonnenphysik .
Contact: Ariane Schad