Ultraviolet Spectrum Study on Explosive Events in the Solar Polar Coronal Hole

Journal of Atmospheric and Environmental Optics ›› 2016, Vol. 11 ›› Issue (1): 22-30.

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Ultraviolet Spectrum Study on Explosive Events in the Solar Polar Coronal Hole

ZHANG Min1,2, WANG Dong1,2

(1 School of Mathematics and Physics, Anhui Jianzhu University, Heifei 230601, China;
2 School of Earth and Space Science, University of Science and Technology of China, Heifei 230026, China)

Received:2015-11-24 Revised:2015-12-09 Online:2016-01-28 Published:2016-01-28

Abstract

Abstract:

Explosive Events (EEs) in the Solar polar coronal hole are observed by N IV line of SOHO/SUMER spectrograph. 323 spectra of EEs in South polar coronal hole and 207 in North polar coronal hole are found. The statistical result shows that the EEs have an occurrence rate of about 10-21~10-20 cm-2s-1 and an average lifetime of around 2 min, which is consistent with the previous results obtained on the disk in quiet-Sun (QS) regions. However, EEs in polar coronal holes (PCHs) generally have a larger spatial size (～4 arcsec) on average. EEs are rarely observed near the limb. The average Doppler shifts deduced from NIV line in PCHs is red, while the Doppler shifts of EEs are mainly blue when a single Gaussian profile is fitted. The velocity of the five typical EE’s blue wing is up to 200 km/s, which is close to the local Alfven speed.

Key words: polar coronal holes, explosive events, UV line

CLC Number:

ZHANG Min, WANG Dong. Ultraviolet Spectrum Study on Explosive Events in the Solar Polar Coronal Hole[J]. Journal of Atmospheric and Environmental Optics, 2016, 11(1): 22-30.

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Ultraviolet Spectrum Study on Explosive Events in the Solar Polar Coronal Hole

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