Solar Magnetic Field Signatures in Helioseismic Splitting Coefficients
Abstract
Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that the frequency splitting is only due to rotation and a large scale magnetic field. We find that the data are best fit by a combination of a poloidal field and a double-peaked near-surface toroidal field. The toroidal fields are centered at r=0.999R_solar and r=0.996R_solar and are confined to the near-surface layers. The poloidal field is a dipole field. The peak strength of the poloidal field is 124 +/- 17G. The toroidal field peaks at 380 +/- 30G and 1.4 +/- 0.2kG for the shallower and deeper fields respectively. The field strengths are highly correlated with surface activity. The toroidal field strength shows a hysteresis-like effect when compared to the global 10.7 cm radio flux. The poloidal field strength shows evidence of saturation at high activity.
Keywords
Cite
@article{arxiv.0910.1597,
title = {Solar Magnetic Field Signatures in Helioseismic Splitting Coefficients},
author = {Charles S. Baldner and H. M. Antia and Sarbani Basu and T. P. Larson},
journal= {arXiv preprint arXiv:0910.1597},
year = {2014}
}
Comments
10 pages, accepted for publication in ApJ