EDP Sciences
Free access
Volume 387, Number 1, May III 2002
Page(s) 335 - 338
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20020393

A&A 387, 335-338 (2002)
DOI: 10.1051/0004-6361:20020393

Influence of wave noise on frequencies and amplitudes of the solar $\vec{p}$-modes

K. Murawski1, L. Nocera2 and E. N. Pelinovsky3

1  Department of Complex Physical Systems, Institute of Physics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin, Poland
2  Institute of Atomic and Molecular Physics, National Research Council, Via Moruzzi 1, 56124 Pisa, Italy
3  Institute of Applied Physics, 46 Ul'anova Street 603600, Nizhny Novgorod, Russia

(Received 16 November 2001 / Accepted 12 March 2002 )

The influence of space- and time-dependent random mass density field, associated with granules, on frequencies and amplitudes of the solar p-modes is examined in the limit of weak random fields and small amplitude oscillations. The p-modes are approximated by the sound waves which propagate in the gravity-free medium. Using a perturbative method, we derive a dispersion relation which is solved for the case of wave noise for which the spectrum $E(k,\omega)\sim E(k) \delta(\omega-c_{\rm r}k)$, where $\delta$ is the Dirac's delta-function and $c_{\rm r}$ is the random phase speed. We find that at $c_{\rm r}=\omega/k$ a resonance occurs at which the cyclic frequency $\omega$ tends to infinity. For values of $c_{\rm r}$ which are close to the resonance point, the frequency shift may be both negative or positive and the imaginary part of the frequency attains the negative (positive) sign for $c_{\rm r}<\omega/k$ ( $c_{\rm r}>\omega/k$).

Key words: convection -- Sun: oscillations -- turbulence

Offprint request: K. Murawski, kmurawsk@tytan.umcs.lublin.pl

© ESO 2002