太阳物理研究组知识库

Based on a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields from Carrington Rotations Nos. 1625 to 2135 (from 1975 February to 2013 March), the sidereal rotation rates of the positive and negative magnetic fields in the latitude range of +/- 60 degrees are obtained, and the rotation rate differences between them are investigated. The time-latitude distribution of the rate differences is shown, which looks like a butterfly diagram at the low and middle latitudes. For comparison, the time-latitude distribution of the longitudinally averaged photospheric magnetic fields is shown. We conclude that the magnetic fields having the same polarity as the leading sunspots at a given hemisphere rotate faster than those exhibiting the opposite polarity at low and middle latitudes. However, at higher latitudes, the magnetic fields having the same polarity as the leading sunspots at a given hemisphere do not always rotate faster than those with the opposite polarity. Furthermore, the relationship between the rotation rate differences and solar magnetic fields is studied through a correlation analysis. Our result shows that the correlation coefficients between them reach maximum values at 13 degrees (14 degrees) latitude in the northern (southern) hemisphere, and change sign at 28 degrees latitude in both hemispheres, then reach their minimum values at 58 degrees (53 degrees) latitude in the northern (southern) hemisphere.