Do Sunspots bubble?

COSTA, A.; STENBORG, G.; VOURLIDAS, A.; SIEYRA, M.V.

Congreso; XI Congreso Latinoamericano de Geofísica Espacial; 2018

Asociación Latinoamericana de Geofísica Espacial

OnJuly 6, 2011, high spatial resolution images of the solar coronarecorded in the extreme ultraviolet (EUV) channels of the AtmosphericImaging Assembly (AIA) instrument onboard the Solar DynamicsObservatory (SDO) detected a recurrent, arc-shaped emission over asunspot in NOAA AR 1243. The emission fronts propagated along acoronal loop bundle rooted in a small area of the dark umbra. Noflaring or coronal mass ejection was associated with this phenomenon.Preliminary analysis suggests that the fronts propagate with anaverage phase velocity of ~50 km/sec, exhibit a periodicity ~3minutes, and appear to be rooted in an umbral dot. In this work, weinvestigate (1) the nature of these quasi-periodic fronts that looklike ?bubbles? (i.e., are they bubbles or are they signatures ofmagnetosonic waves?), and (2) the driver of this recurrentphenomenon. To shed light into the physical nature of these ?bubbles?we run a 2D MHD simulation based on a potential field extrapolationof the sunspot magnetic field in a gravitationally stratifiedatmosphere. The sunspot magnetic field is obtained from line-of-sightmagnetograms provided by the Helioseismic and Magnetic Imager (HMI)instrument onboard SDO. Here we report on the kinematical propertiesand frequency characterization of the event, and describe the detailsof the simulation along with some early outcomes from initial tests.p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left; }p.western { font-family: "Liberation Serif", serif; font-size: 12pt; }p.cjk { font-family: "Droid Sans Fallback"; font-size: 12pt; }p.ctl { font-family: "FreeSans"; font-size: 12pt; }