http://arxiv.org/abs/2211.01140
The distribution of magnetic fields of positive and negative polarities over the surface of the Sun was studied on the basis of synoptic maps NSO Kitt Peak (1978-2016). To emphasize the contribution of weak fields the following transformation of synoptic maps was made: for each synoptic map only magnetic fields with modulus less than 5 G (|B| < 5 G) were left unchanged on each synoptic map while larger or smaller fields were replaced by the corresponding limiting values +5 G or -5 G. Cyclic variations of the magnetic field polarity have been observed associated with two types of magnetic field flows in the photosphere. Rush-to-the-Poles (RTTP) form near the maximum of solar activity and have the same sign as the following sunspots. The lifetime of RTTP is 3 yrs, during which time they drift from latitudes 30 – 40 deg. to the pole, causing the polarity change of the Sun’s polar field. We studied another type of variations which has the form of series of flows with individual flows of 0.5-1 yr and with alternating polarity (ripples). Ripples are located in time between two RTTP and drift from the equator to the latitudes of 50 deg. Magnetic field variations were considered in 6 time intervals along the latitudes +33 deg. in the northern and -33 deg. in the southern hemispheres. The time change of the field strength was approximated by the sinusoidal function. The period of variation of ripples was 1.1 yr for the N-hemisphere and 1.3 yr for the S-hemisphere. The amplitude of variation was higher for the time intervals where the polar field had a positive sign. Within the same flow, fields of positive and negative signs developed in anti-phase.
E. Vernova, M. Tyasto and D. Baranov
Thu, 3 Nov 22
53/59
Comments: 15 pages, 12 figures
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