Statistical Properties of Photospheric Magnetic Elements Observed by SDO/HMI
Abstract
Magnetic elements of the solar surface are studied in magnetograms recorded with the high-resolution Solar Dynamics Observatory / Helioseismic and Magnetic Imager . To extract some statistical and physical properties of these elements (e.g., filling factors, magnetic flux, size, lifetimes), the Yet Another Feature Tracking Algorithm (YAFTA), a region-based method, is employed. An area with 400400 was selected to investigate the magnetic characteristics during the year 2011. The correlation coefficient between filling factors of negative and positive polarities is 0.51. A broken power law fit was applied to the frequency distribution of size and flux. Exponents of the power-law distributions for sizes smaller and greater than 16 arcsec were found to be -2.24 and -4.04, respectively. The exponents of powerlaw distributions for fluxes smaller and greater than 2.6310 Mx were found to be -2.11 and -2.51, respectively. The relationship between the size () and flux () of elements can be expressed by a power-law behavior in the form of . The lifetime and its relationship with the flux and size of quiet-Sun (QS) elements are studied during three days. The code detected patches with lifetimes of about 15 hours, which we call long-duration events. It is found that more than 95\% of the magnetic elements have lifetimes of less than 100 minutes. About 0.05\% of the elements were found with lifetimes of more than 6 hours. The relationships between the size (S), lifetime (T), and the flux (F) for patches in the QS, indicate the powerlaw relationships and , respectively. Executing a detrended fluctuation analysis of the time series of new emerged magnetic elements, we find a Hurst exponent of 0.82, which implies long-range temporal correlation in the system.
Keywords
Cite
@article{arxiv.1707.09291,
title = {Statistical Properties of Photospheric Magnetic Elements Observed by SDO/HMI},
author = {Mohsen Javaherian and Hossein Safari and Neda Dadashi and Markus Josef Aschwanden},
journal= {arXiv preprint arXiv:1707.09291},
year = {2017}
}
Comments
20 pages, 17 figures, submitted to Journal of Solar Physics