EDP Sciences
Free access
Volume 416, Number 3, March IV 2004
Page(s) 1179 - 1186
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20031737

A&A 416, 1179-1186 (2004)
DOI: 10.1051/0004-6361:20031737

Search for 1-10 Hz modulations in coronal emission with SECIS during the August 11, 1999 eclipse

P. Rudawy1, K. J. H. Phillips2, P. T. Gallagher3, D. R. Williams4, B. Rompolt1 and F. P. Keenan5

1  Astronomical Institute of the Wroclaw University, ul Kopernika 11, 51-622 Wroclaw, Poland
2  National Research Council Senior Research Associate, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
3  L-3 Com Analytics Corporation, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
4  Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey RH5 6NT, UK
5  Dept. of Pure and Applied Physics, The Queen's University, Belfast BT7 1NN, N. Ireland, UK

(Received 15 March 2003 / Accepted 11 December 2003)

Results of the search of the periodic changes of the 530.3 nm line intensity emitted by selected structures of the solar corona in the frequency range 1-10 Hz are presented. A set of 12 728 images of the section of the solar corona extending from near the north pole to the south-west were taken simultaneously in the 530.3 nm ("green") line and white-light with the Solar Eclipse Coronal Imaging System (SECIS) during the 143-seconds-long totality of the 1999 August 11 solar eclipse observed in Shabla, Bulgaria. The time resolution of the collected data is better than 0.05 s and the pixel size is approximately 4 arcsec. Using classical Fourier spectral analysis tools, we investigated temporal changes of the local 530.3 nm coronal line brightness in the frequency range 1-10 Hz of thousands of points within the field of view. The various photometric and instrumental effects have been extensively considered. We did not find any indisputable, statistically significant evidence of periodicities in any of the investigated points (at significance level $\alpha=0.05$).

Key words: eclipses -- Sun: corona -- waves -- magnetohydrodynamics (MHD)

Offprint request: P. Rudawy, rudawy@astro.uni.wroc.pl

© ESO 2004