Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-27T02:13:04.297Z Has data issue: false hasContentIssue false
  • English
  • Français

Fe XXIV Emission in Solar Flares Observed with the NRL/ATM XUV Slitless Spectrograph

Published online by Cambridge University Press:  14 August 2015

Kenneth G. Widing
Kenneth G. Widing*
Affiliation:
E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, D.C. U.S.A.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

During the Skylab Mission, the NRL slitless spectrograph photographed a number of flares in the 170–600 Å region with a spatial resolution approaching 2″. At flare maximum the 2s2S1/2 — — 2p2P1/2, 3/2 transitions of Fe XXIV are present, and show the location of the (approx.) 20 × 106 deg plasma with respect to the surface magnetic field and chromospheric (He iiemissions. Three examples are discussed (two only briefly).

In the small, intense disk flare of 1973, August 9 the high temperature region appears at the foot of a low altitude arch. The estimated electron density is 5 × 1011 cm–3.

In the limb flare of 1974, January 15 the hot X-ray emitting component is at a very low altitude compared to the flare loops.

In the impulsive double ribbon flare of 1973, June 15 the Fe XXIV emission is centered over the neutral line, forming a bridge-like structure between magnetic regions of opposite polarity. The estimated electron density is 5 × 1010 cm–3.

The Fe XXIV emission was visible 8 to 10 min as compared with a calculated cooling time by conduction of only 5 min. The lengthened life of the emission may be associated with the observed ‘turbulence’, which inhibits the heat conduction, or alternatively, with a slower energy release prolonged beyond the end of the burst phase.

Type
Part 3: Solar Flares
Information
Symposium - International Astronomical Union , Volume 68: Solar X, Gamma, and EUV Radiation , 1975 , pp. 153 - 163
Copyright
Copyright © Reidel 1975 

References

Cheng, C. C. and Spicer, D. S.: 1975, This volume, p. 423.Google Scholar
Culhane, J. L., Vesecky, J. F., and Phillips, K. J. H.: 1970, Solar Phys. 15, 394.Google Scholar
Dere, K. P.: 1974, private communication.Google Scholar
Dere, K. P. and Kreplin, R. W.: 1974, private communication.Google Scholar
Donnelly, R. F.: 1974, private communication.Google Scholar
Jordan, C.: 1970, Monthly Notices Roy. Astron. Soc. 148, 17.CrossRefGoogle Scholar
Neupert, W. M.: 1971, Phil. Trans. R. Soc. London A 270, 143.Google Scholar
Purcell, J. D. and Widing, K. G.: 1972, Astrophys. J. 176, 239.Google Scholar
Tousey, R., Bartoe, J.-D. F., Bohlin, J. D., Brueckner, G. E., Purcell, J. D., Scherrer, V. E., Sheeley, N. R. Jr., Schumacher, R. J., and VanHoosier, M. E.: 1973, Solar Phys. 33, 265.Google Scholar