New HMI high-cadence vector magnetograms are now available. Observations every 135 or 90 seconds reveal the rapid magnetic evolution occurring during major solar eruptions.
A statistical study of sunspot region properties yields insights on why some are flare-productive.
An atypical X-shaped-ribbon flare provides evidence for 3D magnetic reconnection at a separator.
A statistical study using HMI vector magnetograms predicts the fastest CME that an active region can produce based on its magnetic parameters.
AR 12192 produced six X-class flares, but none was associated with a CME. HMI observations reveal the mild nature of the giant. It has weak relative non-potentiality and strong overlying field; the confined X3 flare leaves little imprint on the photosphere.
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.
We examine the polarization of light emitted by a loop prominence system, near the Fe I line (6173 Å). It has a linearly polarized component, at times up to the level expected from pure Thomson scattering.
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.