EDP Sciences
Free access
Volume 372, Number 3, June IV 2001
Page(s) L53 - L56
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20010607

A&A 372, L53-L56 (2001)
DOI: 10.1051/0004-6361:20010607

Determination of the coronal magnetic field by coronal loop oscillations

V. M. Nakariakov1 and L. Ofman2

1  Physics Department, University of Warwick, Coventry CV4 7AL, UK
2  CUA/NASA Goddard Space Flight Center, 682, Greenbelt, MD 20771, USA
    e-mail: leon.ofman@gsfc.nasa.gov

(Received 30 October 2000 / Accepted 26 April 2001)

We develop a new method for the determination of the absolute value of the magnetic field strength in coronal closed magnetic structures, based on the analysis of flare-generated oscillations of coronal loops. Interpretation of the oscillations observed in terms of global standing kink waves allows to connect the period of the oscillations and the loops length with the magnetic field strength in the loops. For loop oscillations observed with TRACE on 14th July 1998 and 4th July 1999, we estimate the magnetic field strength as 4-30 G. Using TRACE 171 Åand 195 Åimages of the loop, taken on 4th July 1999 to determine the plasma density, we estimate the magnetic field in the loop as $13\pm 9$ G. Improved diagnostic of the loop length, the oscillation period, and the plasma density in the loop will significantly improve the method's precision.

Key words: magnetohydrodynamics (MHD) -- waves -- Sun: corona -- Sun: activity -- Sun: oscillations -- Sun: UV radiation

Offprint request: V. M. Nakariakov, valery@astro.warwick.ac.uk

© ESO 2001

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.