Search for superstrong magnetic fields in active processes on the Sun using spectro-polarimetry within 15 Å around the D3 line

Abstract

ABSTRACT We critically review our previous results on this topic based on the following main points: (i) substantially larger wavelength range around the D3 line was investigated – up to ±15 Å instead of ±2.5 Å in comparison with the previous version of our study, and (ii) greater volume of observational data was analysed, including one X limb flare, additionally. Overall, our study concerns the 2004 July 12 active prominence and the 2014 June 10 limb flare of X1.5 class. For named limb flare, we found reliable and oppositely polarized secondary peaks of the V parameter located at distances of −4.5 and +2.7 Å from the line center. If these features are interpreted as manifestations of the magnetic splitting of the line together with its Doppler shift, then the corresponding magnetic field is ≈2.2 × 105 G, and the radial velocity −46 km s−1. Similar spectral manifestations were also found in the active prominence. For comparison with the theory, the spectral features of the Paschen–Baсk effect at magnetic fields up to 100 kG were studied too. It turned out that the theoretical width of the splitting components is relatively small, 0.3 Å, while the width of the observed peaks is sometimes much larger. On the basis of model calculations, it is shown that in some cases an alternative explanation of the observational data is possible, which includes much weaker magnetic fields (5.5–7.1 kG), but significant macroscopic velocities of different signs, at the level of 50–60 km s−1.