Open AccessWavelet Phase Coherence Analysis: Application to a Quiet‐Sun Magnetic Element
Author(s) -
D. Shaun Bloomfield,
R. T. J. McAteer,
B. W. Lites,
P. G. Judge,
M. Mathioudakis,
F. P. Keenan
Publication year - 2004
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/425300
Subject(s) - physics , wavelet , morlet wavelet , quiet , coherence (philosophical gambling strategy) , wavelet transform , phase (matter) , fourier transform , astrophysics , computational physics , discrete wavelet transform , astronomy , artificial intelligence , quantum mechanics , computer science
A new application of wavelet analysis is presented that utilizes the inherent phase information residing within the complex Morlet transform. The technique is applied to a weak solar magnetic network region, and the temporal variation of phase difference between TRACE 1700 A and SOHO/SUMER C II 1037 A intensities is shown. We present, for the first time in an astrophysical setting, the application of wavelet phase coherence, including a comparison between two methods of testing real wavelet phase coherence against that of noise. The example highlights the advantage of wavelet analysis over more classical techniques, such as Fourier analysis, and the effectiveness of the former to identify wave packets of similar frequencies but with differing phase relations is emphasized. Using cotemporal, ground-based Advanced Stokes Polarimeter measurements, changes in the observed phase differences are shown to result from alterations in the magnetic topology.
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