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.
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.
Analysis of HMI vector magnetic field data before and after a flare illustrate how the energy released can result in a collapse of loop structures, and how the effects can be observed on the solar surface.
We present observations from SDO/HMI of a magnetic transient observed in NOAA 11429 during the M7.9 flare on 13 March 2012. The observed transient showed an impulsive rotation of the field vector in response to the white-light flare.
Even though Solar Cycle 24 is weak, it has still produced some large sunspots. We list the largest sunspots as observed by HMI and discuss some aspects of the data.
Hemispheric helicity preference in groups of active regions with different properties suggests different origins of magnetic twist.