Speaker
Luc Rouppe van der Voort
(University of Oslo)
Description
Ellerman Bombs are strong brightenings of the Halpha wings and commonly interpreted
as signatures of reconnection of kilo-Gauss magnetic fields in the lower atmosphere
in complex active regions. At extreme high spatial resolution and away from disk
center, Ellerman Bombs display distinct flame-like morphology and fast temporal
evolution on a time scale of seconds. Here we report the observation of similar
events in the Quiet Sun, away from Active Regions. In the highest spatial resolution
observations, acquired with the CRISP instrument at the SST over the past seasons, we
see small-scale flame-like brightenings in the Halpha wings, similar to Ellerman
Bombs in Active regions but at smaller spatial scale and temporal duration. Typical
length is 0.5 arcsec, width 0.2 arcsec, and lifetime less than a minute. Co-temporal
spectropolarimetric observations in photospheric Fe I lines show that these Ellerman
brightenings occur in an environment of mixed magnetic polarities which is compatible
with a reconnection scenario. We check for response in hotter diagnostics from IRIS
and AIA/SDO but this is mostly inconclusive given the lower spatial resolution as
compared to SST. Only during the emergence of strong fields in Quiet Sun, in an
ephemeral active region, we find clear response in IRIS SJI 1400, 1330, and 2796 to
the Ellerman brightenings in CRISP Halpha wing.
Primary author
Luc Rouppe van der Voort
(University of Oslo)
