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Pixel Dynamics Analysis of Photospheric Spectral Data
Interim rept. Mar-Aug 2014
NAVAL RESEARCH LAB WASHINGTON DC BEAM PHYSICS BRANCH
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A new method has been developed to analyze high-resolution spectral data of the solar photosphere and chromosphere. The data format is a two-dimensional 2-D time-series of images. The method uses emission or absorption lines in the intensity and polarization data Stokes parameters. Each pixel contains quantitative information on the spectral profiles of selected lines, such as the line width, degree of asymmetry, and peakedness. The 2-D time-series is first averaged in time pixel-by-pixel. A derivative time-series is constructed such that each image in the time-series is characterized by the pixel-by-pixel deviations from the average. The pixel fluctuation distribution PFD function is constructed and its statistical properties are calculated. Such properties including the mean, variance, skewness, and kurtosis are computed as functions of time and are used to precisely quantify temporal variations in the observed spectral data. In this work, the method is applied to photospheric absorption lines Fe I 6301.5 and 6302.5 from quiet-Sun regions and active regions on the solar photosphere, obtained by the vector spectromagnetograph VSM of the Synoptic Optical Long-term Investigations of the Sun SOLIS of the National Solar Observatory NSO.
APPROVED FOR PUBLIC RELEASE