The magnetic field of active region NOAA 11092 shows a persistent counter-clockwise twist in the solar atmosphere from the photosphere to the corona. The subsurface flows associated with this region are twisted in the opposite direction.
New solar fluorine abundance was determined using improved molecular data. The new abundance is slightly lower than the old values previously determined in 1960s.
Combining the outstanding capability of HMI/SDO and NST/BBSO, we studied two rarely observed three-ribbon flares. The flaring site is characterized with an intriguing “fish-bone”-like morphology. These results are discussed in favor of reconnection along the coronal null-line.
Subsurface meridional flow speed shows an anti-correlation with the magnetic flux being transported poleward above the latitude of 35°. In the lower latitude, the residual meridional flow, after a long-time mean profile is subtracted, shows converging flow toward the activity belts.
The Lorentz force acting on the solar atmosphere is useful for diagnosing the eruption dynamics. It is now available as a routine data product.
The statistical analysis of flow fields in and around sunspots indicates a distinct nature of the moat and Evershed flows.
Motivated by recent observations we have explored whether the flux-transport dynamo model can work with multi-cell meridional flow. We find that it can work when certain conditions are fulfilled.
Bertello and collaborators at NSO have made a first attempt to estimate some of the uncertainties in magnetic synoptic maps and evaluated their impact on coronal and heliospheric models. They found that accounting for the statistical uncertainties arising from the distribution of image pixels contributing to each bin in the synoptic map may produce a noticeable change in the results obtained from these models.
Our results show that raising the source surface height 15-30% during solar minimum (depending on the model used) better reproduces the observed IMF open flux from OMNI. We used two different PFSS models and the MDI/HMI magnetograms as input.
Giant convection cells discovered with HMI Doppler data are found to transport angular momentum equatorward. This helps to resolve the 400-year old mystery of the Sun’s rapidly rotating equator.