Bibcode
Schmieder, B.; Guo, Y.; Moreno-Insertis, F.; Aulanier, G.; Yelles-Chaouche, L.; Nishizuka, N.; Harra, L. K.; Thalmann, J. K.; Vargas Dominguez, S.; Liu, Y.
Bibliographical reference
Astronomy and Astrophysics, Volume 559, id.A1, 11 pp.
Advertised on:
11
2013
Journal
Citations
90
Refereed citations
84
Description
Aims: A broad jet was observed in a weak magnetic field area at
the edge of active region NOAA 11106 that also produced other nearby
recurring and narrow jets. The peculiar shape and magnetic environment
of the broad jet raised the question of whether it was created by the
same physical processes of previously studied jets with reconnection
occurring high in the corona. Methods: We carried out a
multi-wavelength analysis using the EUV images from the Atmospheric
Imaging Assembly (AIA) and magnetic fields from the Helioseismic and
Magnetic Imager (HMI) both on-board the Solar Dynamics Observatory,
which we coupled to a high-resolution, nonlinear force-free field
extrapolation. Local correlation tracking was used to identify the
photospheric motions that triggered the jet, and time-slices were
extracted along and across the jet to unveil its complex nature. A
topological analysis of the extrapolated field was performed and was
related to the observed features. Results: The jet consisted of
many different threads that expanded in around 10 minutes to about 100
Mm in length, with the bright features in later threads moving faster
than in the early ones, reaching a maximum speed of about 200 km
s-1. Time-slice analysis revealed a striped pattern of dark
and bright strands propagating along the jet, along with apparent damped
oscillations across the jet. This is suggestive of a (un)twisting motion
in the jet, possibly an Alfvén wave. Bald patches in field lines,
low-altitude flux ropes, diverging flow patterns, and a null point were
identified at the basis of the jet. Conclusions: Unlike classical
λ or Eiffel-tower-shaped jets that appear to be caused by
reconnection in current sheets containing null points, reconnection in
regions containing bald patches seems to be crucial in triggering the
present jet. There is no observational evidence that the flux ropes
detected in the topological analysis were actually being ejected
themselves, as occurs in the violent phase of blowout jets; instead, the
jet itself may have gained the twist of the flux rope(s) through
reconnection. This event may represent a class of jets different from
the classical quiescent or blowout jets, but to reach that conclusion,
more observational and theoretical work is necessary.
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