EDP Sciences
Free access
Issue
A&A
Volume 445, Number 1, January I 2006
Page(s) 337 - 340
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20054049


A&A 445, 337-340 (2006)
DOI: 10.1051/0004-6361:20054049

The flux-gap between bright and dark solar magnetic structures

K. G. Puschmann and E. Wiehr

Institut für Astrophysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
    e-mail: [kgp;ewiehr]@astro.physik.uni-goettingen.de

(Received 21 March 2005 / Accepted 1 September 2005)

Abstract
The upper size limit of solar small-scale magnetic flux concentrations ("G-band bright points", BP) is reconsidered from speckle-reconstructed images taken at the 1-m SST on La Palma. The size-histogram shows a sharp drop towards 250 km diameter, variation of the noise filter threshold diminishes that value due to segmentation of the elongated structures. A further artificial segmentation of still elongated (i.e. not round) BP indicates that the upper limit may well be below 200 km diameter, corresponding to a flux smaller than $2.5\times10^{17}$ Mx which is more than 40 times smaller than that of smallest dark (mini-) pores. BP with diameters of 130 km would already yield to a flux gap of two orders of magnitude. The drop of BP numbers between the histogram maximum and the 90 km resolution limit achieved is found to depend on the low-pass filtering and is thus probably virtual. Higher spatial resolution data will still increase the flux gap between bright and dark solar magnetic flux concentrations which might be a signature of differently deep rooting in the solar atmosphere.


Key words: Sun: activity -- magnetic fields




© ESO 2005

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.