A Coherence Analysis of Fraunhofer-Line Fine Structure and Continuum Brightness Fluctutations Near the Center of the Solar Disk. II

Abstract

view Abstract Citations (33) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Coherence Analysis of Fraunhofer-Line Fine Structure and Continuum Brightness Fluctutations Near the Center of the Solar Disk. II Edmonds, Frank N., Jr. Abstract Spatial cross-correlation analyses between fluctuations in radial velocity, V, and continuum brightness, I, have been carried out for four high-resolution spectrograms of the center of the solar disk obtained by Michard at the Pic-du-Midi Observatory. These analyses employed a coherence technique, and the results are quite similar to those recently obtained from an analysis of Sacramento Peak Observatory spectrograms by Edmonds, Michard, and Servajean. These results suggest that the V fluctuations contain a large-scale oscillatory component poorly correlated with the I fluctuations, and a smaller-scale convective component sigiiificantly correlated with the I fluctuations. An improved method for determining confidence limits for the results of a coherence analysis is presented in the Appendix, and these limits are applied to the results of four spatial coherence analyses. It is shown that these and other estimates of random errors of the statistical analysis cannot explain the differences between the different analyses. Whereas instrumental and atmospheric blurring may be important causes of these differences, it appears that for the most part they are real differences between different samples of photospheric inhomogeneities. The effects of the possible inclination of inhomogeneities found by Evans are also discussed. Confidence limits estimates further show that small variations with wavenumber k1 of power spectra and coherences cannot be considered significant. Publication: The Astrophysical Journal Pub Date: May 1966 DOI: 10.1086/148652 Bibcode: 1966ApJ...144..733E full text sources ADS |