Letter to the Editor

Macrospicules and blinkers as seen in Shutterless EIT 304 Å

¹ Royal Observatory of Belgium, 3 Circular Avenue, 1180 Brussels, Belgium e-mail: mariama@oma.be
² Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland

Received: 20 December 2005
Accepted: 20 April 2006

Abstract

Aims.Small-scale transient phenomena in the solar atmosphere are believed to play a crucial role in the coronal heating and solar wind generation. This study aims at providing new observational evidence on blinkers and macrospicules appearance in imager data and in doing so, establish the long disputed relationship between these phenomena.

Methods.We analyse unique high-cadence images in the transition region He ii 304 Å line obtained in a shutterless mode of the Extreme-ultraviolet Imaging Telescope on board the Solar and Heliospheric Observatory. The data have a cadence of approximately 68 s and a pixel size of 2.62 arcsec. The events are identified through an automatic brightenings identification procedure. Features showing a jet-like structure seen in projection on the disk were selected and their light-curve further analysed.

Results.The temporal evolution of the intensity in three events is shown, two of them seen on-disk as jet-like features and one above the limb. The flux increase, size and duration derived from the light-curve of the on-disk events show an identity with the blinker phenomenon.

Conclusions.The light curves of these events suggest that the off-limb and on-disk features are in fact one and the same phenomenon and therefore that some blinkers are the on-disk counterparts of macrospicules.