The Spectrum of Fluctuations across Penumbral Filaments

Bibcode
1998ApJ...505.1010S
DOI
10.1086/306187
Sánchez-Almeida, J.; Bonet, J. A.
Bibliographical reference

The Astrophysical Journal, Volume 505, Issue 2, pp. 1010-1017.

Advertised on:
10
1998
Journal
The Astrophysical Journal
Number of authors
2
IAC number of authors
2
Citations
22
Refereed citations
17
Description
We estimate the typical spectrum of spatial fluctuations of intensity due to the penumbral filaments. High angular resolution continuum images are used (cut-off frequencies equivalent to 0.28" wavelength of about 5257 Å). The amplitude of the observed spectra follows the modulation transfer function of our optical system. In other words, the spectrum of real penumbral fluctuations seems to be flat up to the higher observable spatial frequency. We expect it to continue far beyond the artificial instrumental cutoff, which implies that the structure of the penumbra remains unresolved to the present solar observations.
Type
Refereed
Magnetic fields
Sunspots

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