Analysis of Differential Rotation of Anti‑Hale Active Regions

Numerous observations show that the rotation rates of active regions (ARs) across the solar disk are higher than those of the local plasma at the surface. This discrepancy is often interpreted as the presence of some “magnetic roots” that are located in faster‑rotating layers of the convection zone and which determine the rotation rate of ARs. This hypothesis may indicate the depth of the generation of a magnetic bundle forming an AR. In the present paper, we analyzed the rotation of anti‑Hale ARs across the solar disk. For the analysis, we used full‑disk line‑of‑sight magnetograms acquired by SDO/HMI. The Crimean catalog of bipolar ARs violating the Hale polarity law for 1989–2018 was used as a list of bipolar reversed polarity groups. In total, the rotation rates of 44 active regions observed between 2010 and 2018 were measured. In order to compare the obtained rotation rates of anti‑Hale ARs with those of the rest ARs, we performed a statistical test χ 2 of both distributions. The test showed these distributions to be statistically indistinguishable. These results suggest that, if the rooting hypothesis is correct, anti-Hale ARs and other ARs are formed within the same depths in the convection zone and there is no reason to suggest a separate mechanism for the formation of anti-Hale ARs.