Astronomy and Astrophysics – Astronomy
Scientific paper
May 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997spd....28.1305l&link_type=abstract
American Astronomical Society, SPD meeting #28, #13.05; Bulletin of the American Astronomical Society, Vol. 29, p.917
Astronomy and Astrophysics
Astronomy
Scientific paper
In this paper we present a new fast spectral scan method to study Hα jets, which are more energetic than regular spicules. The observations achieved high two-dimensional spatial resolution, temporal resolution and spectral resolution simultaneously. We used the Coude spectrograph in the Big Bear Solar Observatory for the Hα data acquisition. The procedure starts with fast spectral scans across the solar surface (600" by 300") at the vicinity of the solar disk center. The guiding system is turned off allowing the Sun to drift smoothly relative to the spectrograph system. A total number of 600 spectral images at 6563A are recorded per scan on an optical disk recorder at a rate of 30 frames/sec. Tracking re-position the system to point to the same initial coordinates on the Sun for new scans. The process repeats every 30 seconds until 60 scans are completed. The stored images are digitized for off-line data analysis. A number of different image processing techniques are used to improve the image quality. These include off-line correlation tracking and running average among various constructed images. From the four-dimensional (x,y,t,wavelength) Hα data arrays, we can reconstruct spectroheliograms (600 by 240 pixels) at different wavelengths. We calculate velocities of jets by measuring Doppler shifts of the Hα absorption line, where we used an optically thin jet model. Velocities of 30 to 50 km/sec for jets are derived. Velocity maps are constructed thereafter for the scanned region, and are compiled as movies. We measure the lifetime and size of the jets from these movies. Lifetimes of a few minutes are observed. Further approximations are made to find out temperature and density of jets by fitting the Hα absorption line profile. The results will enable us to estimate the total mechanical energy released by the jets.
Johannesson Anders
Lee Chik-Yin
Stage Mike
Wang Haimin
Zirin Hal
No associations
LandOfFree
Study of Chromospheric Jets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Study of Chromospheric Jets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Study of Chromospheric Jets will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1147193