The north-south asymmetry of solar activity at high latitudes

Abstract

Solar long-term activity runs at high latitudes in three ways: (i) in phase with solar long-term activity at low latitudes; (ii) in antiphase with solar long-term activity at low latitudes and (iii) does not follow either (i) or (ii), and mainly occurs around the times of maxima of (i) and (ii). In the present study, we investigate the north-south asymmetry of solar activity at high latitudes and found the following. In Case (i), high-latitude filament activity, for example, is inferred to have the same dominant hemisphere as low-latitude activity in a cycle. In Case (ii), the north-south asymmetry of high-latitude activity, represented by both the polar faculae and the Sun's polar field strength, is usually different from that of low-latitude activity in a sunspot cycle, and even in a cycle of high-latitude activity (polar faculae and the Sun's polar field strength), suggesting that the north-south asymmetry of solar activity at high latitudes should have little or no connection with that of low latitudes. In Case (iii), the north-south asymmetry of solar activity at high latitudes (polar flares) should have little connection with that at low latitudes as well. The observed magnetic field at high latitudes is inferred to consist of two components: one comes from the emergence of the magnetic field from the Sun's interior and the other comes from the drift of the magnetic activity at low latitudes.