A time evolution study of limb spicule spectra |
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| Authors: | Kenneth R Krall R J Bessey Jacques M Beckers |
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| Institution: | (1) Department of Physics and Astronomy, University of Wyoming, 82071 Laramie, Wyo., U.S.A.;(2) Sacramento Peak Observatory, Air Force Cambridge Research Laboratory, 88349 Sunspot, N.M., U.S.A. |
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| Abstract: | Time sequences of simultaneous spectra of limb spicules, obtained using the Sacramento Peak Observatory's tower telescope and echelle spectrograph are analyzed. Intensity determinations of H and K, H,  8498 and 8542 of calcium are tabulated for three observing heights. Electron densities averaged over the entire visible lifetimes of spicules are  -6 × 1010 cm–3 at observing heights of 6000km, while maximum and minimum values were -1.1 × 1011 cm–3 at 6000km and - 2 × 1010 cm–3 at 10000km. Electron temperatures range between 12 000 K and 16 000 K. Profile halfwidths indicate turbulent velocities of 12 to 22 km s–1, and spectral tilts are interpreted as caused by differential velocity fields of -3 km s–1 per 1000 km. No large scale spicule expansions or contractions are observed, although possible expulsions or accretions of material are observed. Spicules may be wider in the calcium K and H lines than in H.Now at School of Science and Engineering, The University of Alabama in Huntsville, Huntsville, Alabama. |
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