A search at two eclipses for short-period waves that heat the corona |
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| Authors: | Pasachoff Jay M Babcock Bryce A Russell Kevin D McConnochie Timothy H Diaz J Sebastian |
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| Institution: | (1) Hopkins Observatory, Williams College, Williamstown, Massachusetts, 01267, U.S.A. |
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| Abstract: | As part of a study of the cause of solar coronal heating, we searched for high-frequency ( 1 Hz) intensity oscillations in coronal loops in the Fe xiv] coronal green line. We summarize results from observations made at the 3 November 1994, total solar eclipse from the International Astronomical Union site in Putre, Chile, through partly cloudy skies, and at the 26 February 1998 total solar eclipse from Nord, Aruba, through clear skies. We discuss the image reduction and analysis of two simultaneous series of coronal CCD images digitized at 10 Hz for a total time of 160 s in Chile. One series of images was taken through a filter isolating the 5303 ÅFexiv] coronal green line and the other through a 100 Å filter in the nearby K-corona continuum. We then discuss the modifications made for the 1998 eclipse, and the image reduction and analysis for those image sequences. After standard calibrations and image alignment of both data sets, we use Fourier analysis to search in the Fexiv] channel for intensity oscillations in loops at the base of the corona. Such oscillations in the 1-Hz range are predicted as a result of density fluctuations from the resonant absorption of MHD waves. The dissipation of a significant amount of mechanical energy from the photosphere into the corona through this mechanism could provide sufficient energy to heat the corona. At neither eclipse do we find evidence for oscillations in the Fexiv] green line at a level greater than 2% of coronal intensity. |
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