Spectral manifestations of extremely strong magnetic fields in the sunspot umbra

Fine peculiarities of the Zeeman effect in two big sunspots of October 29, 2003, and October 25, 2014, are analyzed. In order to search spectral evidences of very strong spatially unresolved magnetic fields, the Stokes I ± V and V profiles of the Fe I 6301.5 and 6302.5 Å lines are studied in detail. Confirmed are two effects discovered earlier by Lozitsky (2016): (a) non-parallelism of bisectors in the Fe I 6301.5 line at a distance of about ±250 mÅ from the line center and (b) the existence of weak secondary peaks in Stokes V of the Fe I 6302.5 line placed at a distance of, on the average, ±375 mÅ from the line center. Close correlation (r = 0.77 ± 0.06) was found between (a) and (b) effects indicating the reality of very strong (≈8 kG) unresolved magnetic fields. For the first sunspot, the presence of the abovementioned 8-kG fields is traced along 12 Mm of the sunspot umbra. The filling factor is 0.2-0.3 here, and the relative Doppler velocities (without Evershed's effect) are from −1.7 to −3.1 km/s (plasma lifting). Similar parameters were also obtained for the second sunspot.