Measurement of the Coronal Electron Temperature at the Total Solar Eclipse on 1994 November 3

Abstract

A spectroscopic observation was carried out at the total solar eclipse on 1994 November 3 in Putre, Chile, in order to investigate the electron temperature and the expanding motion of the corona. The shape of weak depressions at 3900 Å and 4300 Å in the continuous coronal spectra was compared with the theoretical electron-scattered coronal spectra; thus, the magnitude of the electron thermal motion was determined directly. It was found that a coronal streamer on the eastern limb and a coronal hole on the south-pole have overall temperatures of about 1.5–1.7 MK and 0.9–1.1 MK, respectively. No significant height variation in the temperature was found in the streamer, while the coronal hole shows evidence of increasing temperature with height. An acceleration of the expanding motion between 1.1 R⊙ and 2.0 R⊙ by ∼ 80 km s−1 was found in the streamer.