| Popis: |
The structure, shape and brightness of the solar corona significantly depend on the activity of the Sun. The crown is very bright and even at maximum solar activity. On these same composite photographs we can observe very bright coronal streamers and other active areas. With minimal solar activity, the corona becomes asymmetric - it extends mainly around the equator. The Ludendorff flatness index (ellipticity) is the first quantitative parameter introduced to analyze the global structure of the solar corona. It is anticorrelated with solar activity and varies between minimum and maximum. The analysis of the coefficient of ellipticity and the phase of the solar cycle shows that the corona in white light during the TSE 2006, 2008, 2009 and 2017 (2 different solar minima) is asymmetric in contrast to the solar corona observed during the solar eclipses of 1990, 1999 and 2012 (solar maximum). In addition, the value of the photometric flatness index at the minimum of the solar cycle can be used to predict the amplitude of the cycle. These results can contribute to the development of the modern idea of the physical characteristics, shape and structure of the solar corona and its evolution within each successive cycle of solar activity. |
