Dead Calm Areas in the Very Quiet Sun

Martínez-González, M. J.; Manso-Sainz, R.; Asensio-Ramos, A.; Hijano, E.
Bibliographical reference

The Astrophysical Journal, Volume 755, Issue 2, article id. 175 (2012).

Advertised on:
8
2012
Number of authors
4
IAC number of authors
3
Citations
35
Refereed citations
28
Description
We analyze two regions of the quiet Sun (35.6 × 35.6 Mm2) observed at high spatial resolution (lsim100 km) in polarized light by the IMaX spectropolarimeter on board the SUNRISE balloon. We identify 497 small-scale (~400 km) magnetic loops, appearing at an effective rate of 0.25 loop h -1 arcsec-2 further, we argue that this number and rate are underestimated by ~30%. However, we find that these small dipoles do not appear uniformly on the solar surface: their spatial distribution is rather filamentary and clumpy, creating dead calm areas, characterized by a very low magnetic signal and a lack of organized loop-like structures at the detection level of our instruments, which cannot be explained as just statistical fluctuations of a Poisson spatial process. We argue that this is an intrinsic characteristic of the mechanism that generates the magnetic fields in the very quiet Sun. The spatio-temporal coherences and the clumpy structure of the phenomenon suggest a recurrent, intermittent mechanism for the generation of magnetic fields in the quietest areas of the Sun.
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