The spatial anisotropy of flares with respect to sunspot groups and vector butterfly diagrams in solar activity cycles 17–20

Abstract

Abstract Data on the location of flares covering solar cycles 17–20 were used to construct vector R(ϕ, t) diagrams for the mean position of the flare scattering centre in the coordinate system of the sunspot centre. The R(ϕ, t)-diagram reveals a spatial anisotropy of the flare process relative to the midline of the ϕ - t-diagram. The Rϕ-component is always directed towards the central midline of the diagram. In turn, the Rλ-component has a character of oppositely directed shears relative to the central midline of the diagram. Thus high-latitude sunspots exibit a positive Rλ > 0 (westward) displacement, while low-latitude sunspots show a negative Rλ < 0 (eastward) one. The vector diagrams of flares reveal a global anisotropy of the flare process. The results are interpreted in terms of a global-scale excitation of flares by wavelike disturbances.