EDP Sciences
Free access
Issue
A&A
Volume 397, Number 3, January III 2003
Page(s) 1069 - 1074
Section Diffuse matter in space
DOI http://dx.doi.org/10.1051/0004-6361:20021538


A&A 397, 1069-1074 (2003)
DOI: 10.1051/0004-6361:20021538

Influence of turbulent magnetic fields on mode frequencies

S. L. Bi1, Y. Liao1 and J. X. Wang2

1  Yunnan Astronomical Observatory and National Astronomical Observatories, Kunming 650011, PR China
2  National Astronomical Observatories, Beijing 100087, PR China

(Received 9 July 2002 / Accepted 18 September 2002)

Abstract
To investigate the physical nature of solar convective zone, we employ the observed frequency shifts of solar oscillations to study the influence of magnetic perturbation inside the Sun on the low- $\ell $ solar p-mode oscillations. We describe the various possibility of frequency shifts for a time-dependent source of MHD turbulence. For the magnetic perturbation contribution, we obtain the frequency shifts of modes with different degree as a function of the spectrum of fluctuating magnetic field. The frequency shift is found to increase with the strength of magnetic fields in solar interior, and its temporal behavior closely follows the phase of the synthetic solar activity cycle. Our analysis indicates that the magnetic activities cause shifts of up to $0.3~\mu{\rm Hz}$. It is obviously shown that mode frequency, which is sensitive to the effect of magnetic fields, can be used as a diagnostic tool for the presence of turbulent magnetic fields in the convection zone.


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

Offprint request: S. L. Bi, wbyw@public.km.yn.cn




© ESO 2003