Orville Chris St. Cyr

New insights on the onsets of coronal mass ejections from soho

Abstract Coronal mass ejections (CMES) are among the most dramatic forms of transient activity occurring in the solar atmosphere. Despite over twenty years of research, many basic questions related to the physics of CMEs have remained unanswered. Observations with the LASCO and EIT experiments on SOHO, combined with recent theoretical modeling, have provided new insights on some of these outstanding questions and have also raised many new ones that need to be addressed in the future. In this paper, we present some of the new results from SOHO pertaining to the source regions and onsets of CMEs, and their evolution in the corona. We emphasize the important role that studies of CMEs will play in the International Solar Cycle Studies program.

Electron-Temperature Maps of the Low Solar Corona: ISCORE Results from the Total Solar Eclipse of 1 August 2008 in China†

We conducted an experiment in conjunction with the total solar eclipse of 1 August 2008 in China to determine the thermal electron temperature in the low solar corona close to the solar limb. The instrument, Imaging Spectrograph of Coronal Electrons (ISCORE), consisted of an eight-inch f/10 Schmidt Cassegrain telescope with a thermoelectrically-cooled CCD camera at the focal plane. Results are electron temperatures of 1 MK at 1.08R⊙ and 1.13R⊙ from the Sun center in the polar and equatorial regions, respectively. This experiment confirms the results of an earlier experiment conducted in conjunction with the total eclipse of 29 March 2006 in Libya, and results are that at a given coronal height the electron temperature in the polar region is larger than at the equatorial region. In this paper we show the importance of using the correct photospheric spectrum pertinent to the solar activity phase at the time of the experiment, which is a required parameter for modeling the underlying theoretical concept for temperature interpretation of the measured intensity ratios using color filters.