Solar chromosphere in D₃ helium line from the spectra of the eclipse on 29 March 2006

Heading: 
Marchenko, GP, 1Akimov, LA, 1Belkina, IL, Velikodsky, YI
1Research Institute of Astronomy at V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2011, 27(4):35-47
Start Page: Solar Physics
Language: Russian
Abstract: 

We present our results of the processing of the slitless spectra of chromosphere in D3 helium line obtained during the solar eclipse on 29 March 2006. The CCD matrix «Cascade-Photometrics 650» with a frequency of 16 frames/s was used for the observations. The map of the height distribution of abso lute values of surface brightness of helium chromosphere is constructed for the latitude interval 30N—10S at the west limb. A relationship between absolute values of surface brightness of chromosphere in D3 helium line and the solar cycle phase is confirmed. It is found that the height distribution of surface brightness of hetium chromosphere has one maximum at a height of about 2000 km. In the lower chromosphere, D3 helium line emission was not detected. This confirms our assumption on the absence of additional maximum at a height of about 300 km in the distribution of the D3 helium line surface brightness during solar minimum period. Moreover, our results confirm that X-ray coronal radiation with λ < 6 nm is the source of helium excitation in the lower chromosphere.

Keywords: D3 helium line, solar chromosphere