A&A 403, 731-741 (2003)
DOI: 10.1051/0004-6361:20030397
Simultaneous observations of solar transition region blinkers and explosive events by SUMER, CDS and BBSO
Are blinkers, explosive events and spicules the same phenomenon?
M. S. Madjarska and J. G. DoyleArmagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland
(Received 16 September 2002 / Accepted 11 March 2003 )
Abstract
The SoHO discovery of the new "blinker" phenomena focused our study on
the search of its relation to already known phenomena such as explosive events and
spicules. The study was performed using a specially planned joint observing program
involving the Coronal Diagnostic Spectrometer (CDS), Solar Ultraviolet Measurements
of Emitted Radiation spectrograph (SUMER) and Big Bear Solar Observatory (BBSO)
magnetograph. Within each blinker, the SUMER data reveal the presence of small-scale
(3´´-5´´), short-lived (2-3 min) bright features not seen in the CDS data
which has sometimes being interpreted as oscillations in SUMER data. With this data
we have clearly identified UV explosive events in CDS data. The explosive events
show a size close to the small-scale brightenings forming the blinker core. However,
they appear in the SUMER data with their typical strong blue and red wings while the
blinker shows at best only a small increase in the emission of the blue and red wings
and in most instances the typical transition region red-shift in the center of the
line. In all cases the explosive events cover one pixel in CDS corresponding to a
size of
. All identified explosive events were
located at the border of the bright network i.e. the blinker, in the network or even
in the internetwork. From this data, we believe that blinkers and explosive events
are two separate phenomena not directly related or triggering each other. In this
study, the Doppler shift was derived in a blinker phenomenon for the first time.
It ranges from -5 to 25
and is predominantly red-shifted. The observed
magnetic flux increase during the blinker phenomena seems to play a crucial role
in the development of this event. We suggest that "blinkers" maybe the on-disk
signature of spicules.
Key words: Sun: corona -- Sun: transition region -- Sun: activity: Sun: UV radiation
Offprint request: M. S. Madjarska, madj@star.arm.ac.uk
© ESO 2003