Bibcode
Fossat, E.; Regulo, C.; Roca-Cortés, T.; Ekhgamberdiev, S.; Gelly, B.; Grec, G.; Khalikov, S.; Khamitov, I.; Lazrek, M.; Palle, P. I.
Bibliographical reference
Astronomy and Astrophysics (ISSN 0004-6361), vol. 266, no. 1, p. 532-536.
Advertised on:
12
1992
Citations
23
Refereed citations
18
Description
Full solar disk observations of radial velocity, obtained with the IRIS
network of resonant scattering spectrometers, are used to analyze the
acoustic p-mode spectrum around the acoustic cut-off frequency. Three
different methods are used to determine it; two use the power spectrum,
while the third uses the phase spectrum. The three values measured
converge to a common value of 5.55 +/- 0.1 mHz, which is higher than any
theoretical prediction. Beyond this frequency, the power spectra still
decreases down to 10 mHz at which point it becomes flat, showing the
presence of some power due to the so-called pseudomodes which we show
are the result of interference between traveling waves. The acoustic
power density measured beyond the cut-off frequency makes it possible to
estimate the energy deposited into the chromosphere about 10 exp 7
erg/sq cm per sec, which is high enough to compensate the losses that
take place in this layer.