Issue |
A&A
Volume 402, Number 3, May II 2003
First Science with the ODIN satellite
|
|
---|---|---|
Page(s) | 1115 - 1127 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20030175 | |
Published online | 23 April 2003 |
Information entropy in solar atmospheric fields
I. Intensity photospheric structures
1
Istituto di Fisica dello Spazio Interplanetario-CNR, 00133 Roma, Italy
2
Dipartimento di Fisica, Università di Roma Tor Vergata, 00133 Roma, Italy
3
Dipartimento di Fisica, Università di L'Aquila, 67010 L'Aquila, Italy
4
Dipartimento di Scienze Fisiche, Università di Napoli Federico II, 80126 Napoli, Italy
Corresponding author: G. Consolini, consolini@ifsi.rm.cnr.it
Received:
30
July
2002
Accepted:
31
January
2003
The existence of a quasi-regular pattern in solar photospheric convective fields is an
open question. In
the present work, this problem is quantitatively approached by means of the normalised information
entropy measure
as introduced by Van Siclen (1997), which reports on the information
content at different scales. Images were acquired at the THEMIS telescope of the European Northern
Observatory by the IPM observing mode, and at the Richard B. Dunn Solar Telescope of the National
Solar Observatory. The evaluation of
in the case of photospheric intensity binarized images
shows the presence of maxima which are evidence of different prominent scales in the photospheric pattern.
The relative positions of these maxima defines an ordering scale ~1.6 Mm in both instantaneous
and average images. This is read as the evidence of a spatio-temporal organization in the evolution of
convective pattern. The emergence of an ordering scale is discussed in the framework of pattern formation
in random systems and in connection with the findings of previous works. By averaging images with time,
an increase of the information content characterized by a coherence time of ~1 h is observed in the
range of scales from 5.0 Mm to 10.0 Mm.
Key words: Sun: photosphere / Sun: granulation / methods: statistical
© ESO, 2003
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