EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 461/1 Article
Free access article

Issue A&A
Volume 461, Number 1, January I 2007
Page(s) L1 - L4
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20066415



A&A 461, L1-L4 (2007)
DOI: 10.1051/0004-6361:20066415

Letter

Solar atmospheric oscillations and the chromospheric magnetic topology

A. Vecchio1, G. Cauzzi1, K. P. Reardon1, K. Janssen1, and T. Rimmele2

1  INAF - Osservatorio Astrofisico di Arcetri, 50125 Firenze, Italy
    e-mail: vecchio@arcetri.astro.it
2  National Solar Observatory, PO Box 62, Sunspot NM 88349, USA

(Received 19 September 2006 / Accepted 1 November 2006)

Abstract
Aims.We investigate the oscillatory properties of the quiet solar chromosphere in relation to the underlying photosphere, with particular regard to the effects of the magnetic topology.
Methods.For the first time we perform a Fourier analysis on a sequence of line-of-sight velocities measured simultaneously in a photospheric (Fe I 709.0 nm) and a chromospheric line (Ca II 854.2 nm). The velocities were obtained from full spectroscopic data acquired at high spatial resolution with the Interferometric BIdimensional Spectrometer (IBIS). The field of view encompasses a full supergranular cell, allowing us to discriminate between areas with different magnetic characteristics.
Results.We show that waves with frequencies above the acoustic cut-off propagate from the photosphere to upper layers only in restricted areas of the quiet Sun. A large fraction of the quiet chromosphere is in fact occupied by "magnetic shadows", surrounding network regions, that we identify as originating from fibril-like structures observed in the core intensity of the Ca II line. We show that a large fraction of the chromospheric acoustic power at frequencies below the acoustic cut-off, residing in the proximity of the magnetic network elements, directly propagates from the underlying photosphere. This supports recent results arguing that network magnetic elements can channel low-frequency photospheric oscillations into the chromosphere, thus providing a way to input mechanical energy in the upper layers.


Key words: Sun: chromosphere -- Sun: magnetic fields -- Sun: oscillations



© ESO 2006


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.