In this work we present some applications of wavelet analysis to the dynamics of the photosphere as obtained from a good serie of high spatial resolution white light images taken at the Vacuum Tower Telescope (VTT) at the NSO/SPO in October 1996. The use of wavelets, in particular the space-scale localization property, permits us the recognition of coherent structures at different scales; by using a related method known as MultiResolution Analysis (MRA) we compute the wavelet spectrum for each image in our data set and with this informations we define a characteristic scale; for space and time distributions of wavelet spectra we compute the flatness which is a good marker for the presence of space and time intermittency. We verify the existence of a characteristic scale and we study its temporal variation; we find a spatial flatness near gaussian value for all considered scales, while the flatness computed on the derivatives of wavelet coefficients temporal distribution shows a strong dependence of its maximum with the scale.

Wavelet analysis of spatial coherent structures in the photosphere

PIETROPAOLO, Ermanno;
1999-01-01

Abstract

In this work we present some applications of wavelet analysis to the dynamics of the photosphere as obtained from a good serie of high spatial resolution white light images taken at the Vacuum Tower Telescope (VTT) at the NSO/SPO in October 1996. The use of wavelets, in particular the space-scale localization property, permits us the recognition of coherent structures at different scales; by using a related method known as MultiResolution Analysis (MRA) we compute the wavelet spectrum for each image in our data set and with this informations we define a characteristic scale; for space and time distributions of wavelet spectra we compute the flatness which is a good marker for the presence of space and time intermittency. We verify the existence of a characteristic scale and we study its temporal variation; we find a spatial flatness near gaussian value for all considered scales, while the flatness computed on the derivatives of wavelet coefficients temporal distribution shows a strong dependence of its maximum with the scale.
92-9092-792-5
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/39265
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