TITLE:
Relationship between the Sunspot Number and Solar Polar Field by Wavelet-Based Multifractal Analysis
AUTHORS:
Fumio Maruyama
KEYWORDS:
Sunspot Number, Solar Polar Field, Wavelet, Multifractal
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.7 No.5,
May
17,
2019
ABSTRACT:
There is increasing interest in
finding the relation between the sunspot number (SSN) and solar polar field. In
general, fractal properties may be observed in the time series of the dynamics
of complex systems, such as solar
activity and climate. This study investigated the relations between the SSN and solar
polar field by performing a multifractal analysis. To investigate the change in
multifractality, we applied a wavelet transform to time series. When the SSN was maximum and minimum, the SSN showed monofractality or
weak multifractality. The solar polar field showed weak multifractality when
that was maximum and minimum. When the SSN became maximum, the fractality of
the SSN changed from multifractality to monofractality. The multifractality of
SSN became large before two years of SSN maximum, then
that of the solar polar field became large and changed largely. It was found
that the change in SSN triggered the change in the solar polar field. Hence,
the SSN and solar polar field were closely correlated from the view point of fractals. When the maximum
solar polar field before the maximum SSN was larger, the maximum SSN of the
next cycle was larger. The formation of the magnetic field of the sunspots was
correlated with the solar polar field.