The effect of seeing on solar magnetic flux mesurments
Abstract
We investigate the influence of seeing upon measurement of magnetic flux of photospheric fields. For this purpose we quantify seeing variation in one day's observation at Big Bear Solar Observatory in terms of the Fried function, a Modulation Transfer Function for the atmospheric seeing. The temporal variation of seeing quality is compared with that of magnetic flux measured in a quiet region with size 5′ x 4′ near the solar disk center. A good correlation is found between the seeing change and apparent evolution of magnetic flux values, implying, as a possibility, that magnetic flux measurement might have been modulated by seeing. Based on a simple model of ensembles of Gaussian magnetic elements we argue that even the net flux as well as the total flux can change due to seeing variation if the magnetograph has a finite detection threshold and if the intrinsic fluxes in one and the other polarities are unbalanced.
Additional Information
© 1997 Kluwer Academic Publishers. Received 13 August, 1996; in final form 15 October, 1996. We thank Dr C. U. Keller for critical comments. One of us (JL) has been supported by the 1995 KOSEF Post-Doc program and HSY by the Basic Science Research Institute Prograrn, Ministry of Education 1996 (BSRI-96–5408). The work at Big Bear Solar Observatory was supported by NASA under Grant NAGW-1972.Additional details
Identifiers
- Eprint ID
- 106202
- DOI
- 10.1023/a:1004962105138
- Resolver ID
- CaltechAUTHORS:20201021-171001410
Related works
- Describes
- 10.1023/a:1004962105138 (DOI)
Funding
- Korea Science and Engineering Foundation (KOSEF)
- Ministry of Education (Korea)
- BSRI-96-5408
- NASA
- NAGW-1972
Dates
- Created
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2020-10-23Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field