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Most models of solar eruptions assume that coronal field lines are anchored in the dense photosphere and thus the photospheric magnetic fields would not have rapid, irreversible changes associated with eruptions resulted from the coronal…
The abrupt and permanent changes of photospheric magnetic field in the localized regions of active regions during solar flares called magnetic imprints (MIs), have been observed for the past nearly three decades. The well known "coronal…
The rapid and irreversible change of photospheric magnetic fields associated with flares has been confirmed by many recent studies. These studies showed that the photospheric magnetic fields respond to coronal field restructuring and turn…
It is well known that the long-term evolution of the photospheric magnetic field plays an important role in building up free energy to power solar eruptions. Observations, despite being controversial, have also revealed a rapid and…
Photospheric magnetic field not only plays important roles in building up free energy and triggering solar eruptions, but also has been observed to change rapidly and permanently responding to the coronal magnetic field restructuring due to…
Aims: Changes of the magnetic field and the line-of-sight velocities in the photosphere are being reported for an M-class flare that originated at a $\delta$-spot belonging to active region NOAA 11865. Methods: High-resolution ground-based…
The solar active region photospheric magnetic field evolves rapidly during major eruptive events, suggesting appreciable feedback from the corona. Previous studies of these "magnetic imprints" are mostly based on line-of-sight only or…
Solar flares are known to leave imprints on the magnetic field at the photosphere, often manifested as an abrupt and permanent change in the downward-directed Lorentz force in localized areas inside the active region. Our study aims to…
Significant photospheric magnetic field changes during major solar eruptions -- interpreted as coronal feedback from eruptions to the photosphere -- are well-observed. However, analogous short-time scale field changes preceding eruptions…
Abrupt and permanent changes of photospheric magnetic fields have been observed during solar flares. The changes seem to be linked to the reconfiguration of magnetic fields, but their origin is still unclear. We carried out a statistical…
We report the evolution of magnetic field and its energy in NOAA active region 11158 over 5 days based on a vector magnetogram series from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). Fast flux…
During eruptive flares, vector magnetograms show increasing horizontal magnetic field and downward Lorentz force in the Sun's photosphere around the polarity-inversion line. Such behavior has often been associated with the implosion…
Coronal electric currents store the magnetic energy that is released in solar flares and coronal mass ejections (CMEs). Here, we use photospheric vector magnetic field observations to study currents in active regions 10930 and 11158, which…
We analyze high-cadence vector magnetograms (135~s) and flare-ribbon observations of 37 flares from the Solar Dynamics Observatory to understand the spatial and temporal properties of changes in the photospheric vector magnetic field and…
Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…
Solar flares are driven by release of free magnetic energy and often associated with restructurization of the magnetic field topology. Yet, observations of evolving magnetic field in the flaring volume are limited to very few cases…
It has been found that photospheric magnetic fields can change in accordance with the three-dimensional magnetic field restructuring following solar eruptions. Previous studies mainly use vector magnetic field data taken for events near the…
The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. This Letter reports such a rapid change of magnetic fields during the 2011 February 13 M6.6 flare in…
We have analyzed multi-wavelength observations and magnetic-field data for the solar flare of May 10, 2012 (04:18 UT) and have detected a sign inversion of the signal in the line-of-sight magnetic measurements in the umbra of a small spot.…
Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…