Bibcode
Pérez Hernández, F.; González Hernández, I.
Referencia bibliográfica
Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21 ASP Conference Series, Vol. 416, proceedings of a conference held 11-15 August 2008 at the High Altitude Observatory, Boulder, Colorado, USA. Edited by Mausumi Dikpati, Torben Arentoft, Irene González Hernández, Charles Lindsey, and Frank Hill. San Francisco: Astronomical Society of the Pacific, 2009., p.159
Fecha de publicación:
12
2009
Número de citas
0
Número de citas referidas
0
Descripción
Seismic images of magnetic activity on the far surface of the Sun are
calculated using the seismic holography technique. The method is based
on the comparison of waves going in and out of a particular point
(focus) in the Sun and requires computation of the Green's function
representing the disturbance measured on the front side (pupil) from a
unit acoustic impulse originating at the focus. In this work we describe
how to compute Green's functions for the Lagrangian pressure fluctuation
from a spherical polar expansion of the adiabatic wave equations in the
Cowling approximation. A comparison between the results obtained by
using the ray approximation and the spherical polar expansion is shown.
We use the acoustic-gravity wave equation in the plane-parallel limit in
both cases and for the latter we take the asymptotic approximation for
the radial part of the solution. We also show that the phase shift in
the Green's functions due to incorrect modeling of the uppermost layers
of the Sun can be estimated from the eigenfrequencies of the normal
oscillation modes.