First Synoptic Maps of Photospheric Vector Magnetic Field from SOLIS/VSM: Non-Radial Magnetic Fields and Hemispheric Pattern of Helicity

We use daily full-disk vector magnetograms from Vector Spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) system to synthesize the first Carrington maps of the photospheric vector magnetic field. We describe these maps and make a comparison of observed radial field with the radial field estimate from LOS magnetograms. Further, we employ these maps to study the hemispheric pattern of current helicity density, Hc, during the rising phase of the solar cycle 24. Longitudinal average over the 23 consecutive solar rotations shows a clear signature of the hemispheric helicity rule, i.e. Hc is predominantly negative in the North and positive in South. Although our data include the early phase of cycle 24, there appears no evidence for a possible (systematic) reversal of the hemispheric helicity rule at the beginning of cycle as predicted by some dynamo models. Further, we compute the hemispheric pattern in active region latitudes (-30 deg le theta le 30 deg) separately for weak (100< |B_r| <500 G)and strong (|B_r|>1000 G) radial magnetic fields. We find that while the current helicity of strong fields follows the well-known hemispheric rule (i.e., theta . Hc < 0), H_c of weak fields exhibits an inverse hemispheric behavior (i.e., theta . Hc > 0) albeit with large statistical scatter. We discuss two plausible scenarios to explain the opposite hemispheric trend of helicity in weak and strong field region.

Super Fast and Quality Azimuth Disambiguation

The paper presents the possibility of fast and quality azimuth disambiguation of vector magnetogram data regardless of location on the solar disc. The new Super Fast and Quality (SFQ) code of disambiguation is tried out on well-known models of Metcalf et al. (2006), Leka et al. (2009) and artificial model of fixed configuration AR 10930 (Rudenko et al., 2010). We make comparison of Hinode SOT SP vector magnetograms of AR 10930 disambiguated with three codes: SFQ, NPFC (Georgoulis, 2005), and SME (Rudenko et al., 2010). We exemplify the SFQ disambiguation of SDO/HMI measurements of the full disc. The preliminary examination indicates that the SFQ algorithm provides better quality than NPFC and is comparable to SME. In contrast to other codes, SFQ supports relatively high quality of results regardless of the magnetogram proximity to the limb (when being very close to the limb, it is efficient unlike all other algorithms).