Sensitivity of oscillation frequencies to temporal variations in the tachocline region

Eff-Darwich, A.; Pérez Hernández, F.; Korzennik, S. G.
Bibliographical reference

In: Proceedings of the SOHO 10/GONG 2000 Workshop: Helio- and asteroseismology at the dawn of the millennium, 2-6 October 2000, Santa Cruz de Tenerife, Tenerife, Spain. Edited by A. Wilson, Scientific coordination by P. L. Pallé. ESA SP-464, Noordwijk: ESA Publications Division, ISBN 92-9092-697-X, 2001, p. 289 - 293

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2001
Number of authors
3
IAC number of authors
0
Citations
2
Refereed citations
2
Description
We have analyzed the differences in the oscillation eigenfrequencies measured over four years of GONG, SOI/MDI and LOWL observations (1996 to 1999). We have inverted these data to look for signatures of the solar activity cycle on the stratification. A one-dimensional structure inversion code was used to study temporal variations of the radial distribution of the sound speed at the boundary between the radiative and convective zones. Such variations could be an indication of the presence of a toroidal magnetic field anchored in this region. We have not found systematic variations of the stratification at the base of the convection zone. However we set an upper limit to fractional variations of the sound speed of approximately 4×10-5.