Search for Rapid Changes in the Visible-Light Corona during the 21~June 2001 Total Solar Eclipse |
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Pawel Rudawy Submitted: 2010-09-28 09:13
Some 8000 images obtained with the SECIS fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analyzed to search for short-period oscillations in intensity that could
be a signature of solar coronal heating mechanisms by MHD wave dissipation.
Images were taken in white-light and Fe XIV green-line (530.3 nm) channels over 205 seconds (frame rate 39 per sec), approximately the length of eclipse totality
at this location, with a pixel size of four arcseconds square. The data are of considerably better quality than were obtained during the 11 August 1999 total
eclipse, observed by us (Rudawy et al.: Astron. Astrophys. 416, 1179, 2004), in that the images are much better exposed and enhancements in the drive system
of the heliostat used gave a much improved image stability. Classical Fourier and wavelet techniques have been used to analyze the emission at 29518 locations, of which 10714 had emission at reasonably high levels, searching for periodic
fluctuations with periods in the range 0.1?17 seconds (frequencies 0.06x10 Hz). While a number of possible periodicities were apparent in the wavelet analysis,
none of the spatially and time-limited periodicities in the local brightness curves was found to be physically important. This implies that the pervasive Alfvén
wave-like phenomena (Tomczyk et al.: Science 317, 1192, 2007) using polarimetric observations with the CoMP instrument do not give rise to significant oscillatory intensity fluctuations.
Authors: P. Rudawy, K.J.H. Phillips, A. Buczylko, D.R. Williams, F.P. Keenan
Projects: None
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Publication Status: Solar Physics (in press)
Last Modified: 2010-09-28 09:31
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