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

[1] 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-..