TY - GEN
T1 - Rapid changes of sunspot structure associated with solar eruptions
AU - Wang, Haimin
AU - Liu, Chang
PY - 2011/8
Y1 - 2011/8
N2 - In this paper we summarize the studies of flare-related changes of photospheric magnetic fields. When vector magnetograms are available, we always find an increase of transverse field at the polarity inversion line (PIL). We also discuss 1 minute cadence line-of-sight MDI magnetogram observations, which usually show prominent changes of magnetic flux contained in the flaring α spot region. The observed limb-ward flux increases while disk-ward flux decreases rapidly and irreversibly after flares. These observations provides evidences, either direct or indirect, for the theory and prediction of Hudson, Fisher &Welsch (2008) that the photospheric magnetic fields would respond to coronal field restructuring and turn to a more horizontal state near the PIL after eruptions. From the white-light observations, we find that at flaring PIL, the structure becomes darker after an eruption, while the peripheral penumbrae decay. Using highresolution Hinode data, we find evidence that only dark fibrils in the "uncombed" penumbral structure disappear while the bright grains evolve to G-band bright points after flares.
AB - In this paper we summarize the studies of flare-related changes of photospheric magnetic fields. When vector magnetograms are available, we always find an increase of transverse field at the polarity inversion line (PIL). We also discuss 1 minute cadence line-of-sight MDI magnetogram observations, which usually show prominent changes of magnetic flux contained in the flaring α spot region. The observed limb-ward flux increases while disk-ward flux decreases rapidly and irreversibly after flares. These observations provides evidences, either direct or indirect, for the theory and prediction of Hudson, Fisher &Welsch (2008) that the photospheric magnetic fields would respond to coronal field restructuring and turn to a more horizontal state near the PIL after eruptions. From the white-light observations, we find that at flaring PIL, the structure becomes darker after an eruption, while the peripheral penumbrae decay. Using highresolution Hinode data, we find evidence that only dark fibrils in the "uncombed" penumbral structure disappear while the bright grains evolve to G-band bright points after flares.
KW - Sun: activity
KW - Sun: coronal mass ejections (CMEs)
KW - Sun: flares
KW - Sun: magnetic fields
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U2 - 10.1017/S1743921311014943
DO - 10.1017/S1743921311014943
M3 - Conference contribution
AN - SCOPUS:84883034582
SN - 9780521760621
T3 - Proceedings of the International Astronomical Union
SP - 15
EP - 20
BT - The Physics of Sun and Star Spots
PB - Cambridge University Press
ER -