EDP Sciences
Free Access
Volume 403, Number 2, May IV 2003
Page(s) 731 - 741
Section Diffuse matter in space
DOI https://doi.org/10.1051/0004-6361:20030397

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. Doyle

Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland
(Received 16 September 2002 / Accepted 11 March 2003 )

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 $4\arcsec \times 4\arcsec{-}6\arcsec$. 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  $\rm km \; s^{-1}$ 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

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