We determine the frequencies of solar oscillations covering a wide range of degree (100 < l < 4000) and frequency (1.5 < ν < 10 mHz) using the ring diagram technique applied to power spectra obtained from MDI (Michelson Doppler Imager) data. The f-mode ridge extends up to l ≈ 3000, where the line width becomes very large, implying a damping time which is comparable to the time period. The frequ...

Oscillations and propagating waves are commonly seen in high-resolution observations of filament threads, i.e., the fine-structures of solar filaments/prominences. Since the temperature of prominences is typically of the order of 104 K, the prominence plasma is only partially ionized. In this paper, we study the effect of neutrals on the wave propagation in a filament thread modeled as a partia...

Recent observations of coronal-loop waves by TRACE and within the corona as a whole by CoMP clearly indicate that the dominant oscillation period is 5 minutes, thus implicating the solar p modes as a possible source. We investigate the generation of tube waves within the solar convection zone by the buffeting of p modes. The tube waves—in the form of longitudinal sausage waves and transverse ki...

Using 17 hours of full-disk MDI Doppler data we have investigated the center-to-limb variation of the oscillatory wave spectrum of the solar photosphere. Power distributions in the khν-plane are calculated for fields of 20◦ × 20◦ on the Sun, centered at every 10◦ heliographic latitude. From the centerto-limb variation of the power in the f mode and the lowest 7 p modes we obtain information abo...

The goal of this research is to investigate how magnetic field affects the dynamics of granular convection and excitation of solar oscillations by means of realistic numerical simulations. We have used a 3D, compressible, non-linear radiative magnetohydrodynamics code developed at the NASA Ames Research Center. This code takes into account several physical phenomena: compressible fluid flow in ...

We have observed evidence for p-mode oscillations in the G0 IV star Boo (V = 2:68). This represents the rst clear evidence of solar-like oscillations in a star other than the Sun. We used a new technique which measures uctuations in the temperature of the star via their eeect on the equivalent widths of the Balmer lines. The observations were obtained over six nights with the 2.5 m Nordic Optic...

A recent study by Nakariakov et al. pointed out that the dispersion relation of MHD sausage mode oscillations has been incorrectly applied to coronal loops, neglecting the highly dispersive nature of the phase speed and the long-wavelength cutoff of the wave number. In the light of these new insights we revisit previous observations that have been interpreted in terms of MHD sausage mode oscill...

Oscillations of the Sun and solar-like stars are believed to be excited stochastically by convection near the stellar surface. Theoretical modeling predicts that the resulting amplitude increases rapidly with the luminosity of the star. Thus one might expect oscillations of substantial amplitudes in red giants with high luminosities and vigorous convection. Here we present evidence that such os...