European Solar Physics Online Seminar

Following an initiative by the University of Oslo the MPS will participate in the "European Solar Physics Online Seminar" series (ESPOS). Details can be found here: https://folk.uio.no/tiago/espos/
The aim of this video conference series is to promote ideas more widely with a specialized audience, and give some exposure to cutting-edge research for students and other young researchers that do not regularly travel to conferences. The ESPOS series is planned to take place every second Thursday at 11am.

Location: Osservatorio Astrofisico di Catania (broadcasted at MPS)
We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of active region NOAA 12529. IRIS data are complemented by full-disk, simultaneous observations of the Solar Dynamics Observatory satellite, relevant to the photosphere and the corona. The photospheric configuration of the EFR is also analysed by measurements taken with the spectropolarimeter onboard the Hinode satellite, when the EFR was fully developed. Recurrent intense brightenings that resemble UV bursts, with counterparts in all coronal passbands, are identified at the edges of the EFR. Jet activity is also found at chromospheric and coronal levels, near the observed brightness enhancement sites. Analysis of the IRIS line profiles reveals heating of dense plasma in the low solar atmosphere and the driving of bi-directional, high-velocity flows with speeds up to 100 km/s at the same locations. Comparing these signatures with previous observations and numerical models, we suggest evidence of several long-lasting, small-scale magnetic reconnection episodes between the emerging bipole and the ambient field. This process leads to the cancellation of a pre-existing photospheric flux concentration of the plage with the opposite polarity flux patch of the EFR. Moreover, the reconnection appears to occur higher in the atmosphere than usually found in UV bursts, explaining the observed coronal counterparts. [more]
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