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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, A09S09, doi:10.1029/2004JA010938, 2005

Three-dimensional estimates of the coronal electron density at times of extreme solar activity

M. D. Butala

Department of Electrical and Computer Engineering, Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA


R. A. Frazin

Department of Electrical and Computer Engineering, Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA


F. Kamalabadi

Department of Electrical and Computer Engineering, Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA


Abstract

This paper presents quantitative three-dimensional (3-D) reconstructions of the electron density (Ne) in the solar corona between 1.14 and 2.7 solar radii (R ⊙ ) formed from polarized brightness (pB) measurements made by the Mauna Loa Solar Observatory Mark-IV (Mk4) K-coronameter at the time of the extreme solar events of October and November 2003. The 3-D reconstructions are made by a process called solar rotational tomography that exploits the view angles provided by solar rotation during a 2-week period. Although this method is incapable of resolving dynamic evolution on timescales of less than about 2 weeks, a qualitative comparison of the reconstructions to instantaneous Extreme ultraviolet Imaging Telescope images (EIT) shows good agreement between coronal holes, active regions, and “quiet Sun” structures on the disk and their counterparts in the corona at 1.2 R ⊙ .

Received 30 November 2004; accepted 22 March 2005; published 30 September 2005.

Keywords: tomography; electron density; solar corona; coronagraph; image reconstruction.

Index Terms: 7509 Solar Physics, Astrophysics, and Astronomy: Corona; 7511 Solar Physics, Astrophysics, and Astronomy: Coronal holes; 6982 Radio Science: Tomography and imaging (7270, 8180); 7594 Solar Physics, Astrophysics, and Astronomy: Instruments and techniques.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 4312304 bytes)

Citation: Butala, M. D., R. A. Frazin, and F. Kamalabadi (2005), Three-dimensional estimates of the coronal electron density at times of extreme solar activity, J. Geophys. Res., 110, A09S09, doi:10.1029/2004JA010938.