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In the Sun, the properties of acoustic modes are sensitive to changes in the magnetic activity. In particular, mode frequencies are observed to increase with increasing activity level. Thanks to CoRoT and Kepler, such variations have been…

We argue that the solar g-modes are unlikely to have caused the discrete peaks in the power spectrum of the solar wind flux observed by Thomson et al. (1995). The lower limit to the energy of individual g-modes, using the amplitudes given…

Astrophysics · Physics 2016-08-30 Pawan Kumar , Eliot Quataert , John N. Bahcall

We examine the solar-cycle variation of the power in the low-degree helioseismic modes by looking at binned power spectra from 45 years of observations with the Birmingham Solar Oscillations Network, which provides a more robust estimate of…

Solar and Stellar Astrophysics · Physics 2022-06-22 Rachel Howe , W. J. Chaplin , Y. P. Elsworth , S. J. Hale , M. B. Nielsen

Here we present a detailed analysis of solar acoustic mode frequencies and their rotational splittings for modes with degree up to 900. They were obtained by applying spherical harmonic decomposition to full-disk solar images observed by…

Astrophysics · Physics 2008-08-22 M. C. Rabello-Soares , S. G. Korzennik , J. Schou

Hydrodynamical, 3D simulations of the outer layers of the Sun and Alpha Cen A are used to obtain constraints on the properties of turbulent convection in such stars. These constraints enable us to compute - on the base of a theoretical…

Astrophysics · Physics 2007-05-23 R. Samadi , M. J. Goupil , F. Baudin , D. Georgobiani , R. Trampedach , R. Stein , A. Nordlund

We consider damping and absorption of solar $p$ modes due to their energy loss to magnetic tube waves that can freely carry energy out of the acoustic cavity. The coupling of $p$ modes and sausage tube waves is studied in a model atmosphere…

Solar and Stellar Astrophysics · Physics 2015-06-19 Andrew Gascoyne , Rekha Jain , Bradley Hindman

We measure the mean frequencies of acoustic waves propagating toward and away from a sunspot employing a spot-centered Fourier-Hankel decomposition of p-mode amplitudes as measured from a set of observations made at the South Pole in 1991.…

Astrophysics · Physics 2007-05-23 D. C. Braun , Y. Fan , C. Lindsey , S. M. Jefferies

A Bayesian probability based approach is applied to the problem of detecting and parameterizing oscillations in the upper solar atmosphere for the first time. Due to its statistical origin, this method provides a mechanism for determining…

Astrophysics · Physics 2008-12-18 M. S. Marsh , J. Ireland , T. Kucera

Dispersive delays due to the Solar wind introduce excess noise in high-precision pulsar timing experiments, and must be removed in order to achieve the accuracy needed to detect, e.g., low-frequency gravitational waves. In current pulsar…

We compute the p-mode oscillation frequencies and frequency splittings that arise in a two-dimensional model of the Sun that contains toroidal magnetic fields in its interior.

Astrophysics · Physics 2008-10-29 Linghuai Li , Sarbani Basu , Sabatino Sofia , Pierre Demarque

We calculate accurate solar models and report the detailed time dependences of important solar quantities. We use helioseismology to constrain the luminosity evolution of the sun and report the discovery of semi-convection in evolved solar…

Astrophysics · Physics 2008-11-26 John N. Bahcall , M. H. Pinsonneault , Sarbani Basu

At high frequencies beyond the acoustic cut-off, a peak-like structure is visible in the solar power spectrum. Known as the pseudo-modes, their frequencies have been shown to vary in anti-phase with solar magnetic activity. In this work, we…

Solar and Stellar Astrophysics · Physics 2024-09-06 Laura Jade Millson , Anne-Marie Broomhall , Tishtrya Mehta

Activity-related variations in the solar oscillation properties have been known for 30 years. However, the relative importance of the different contributions to the observed variations is not yet fully understood. Our goal is to estimate…

Solar and Stellar Astrophysics · Physics 2016-10-24 A. R. G. Santos , M. S. Cunha , P. P. Avelino , W. J. Chaplin , T. L. Campante

We analyze more than 5000 days of high-quality Sun-as-a-star, radial velocity GOLF and photometric VIRGO/SPM helioseismic observations to extract precise estimates of the visibilities of the low-degree p modes and the m-height ratios of the…

Solar and Stellar Astrophysics · Physics 2015-05-27 David Salabert , Jerome Ballot , Rafael A. Garcia

Turbulent motions in stellar convection zones generate acoustic energy, part of which is then supplied to normal modes of the star. Their amplitudes result from a balance between the efficiencies of excitation and damping processes in the…

Astrophysics · Physics 2009-11-13 K. Belkacem , R. Samadi , M. J. Goupil , M. A. Dupret

We used the Pixelised Wavelet Filtering (PWF) method to compute narrow-band power maps of SDO/AIA imaging datasets in the 1700 \AA{}, 1600 \AA{} and 304 \AA{} bandpasses that correspond to different heights. The cut-off frequency was…

Solar and Stellar Astrophysics · Physics 2014-04-15 Ding Yuan , R. Sych , V. E. Reznikova , V. M. Nakariakov

Most studies of quasi-periodic pulsations in solar flares have identified characteristic periods in the 5 - 300s range. Due to observational limitations there have been few attempts to probe the < 5s period regime and understand the…

Solar and Stellar Astrophysics · Physics 2024-06-12 Andrew R. Inglis , Laura A. Hayes

We present a Bayesian analysis of data from the FIELDS instrument on board the Parker Solar Probe (PSP) spacecraft with the aim of constraining low frequency ($\lesssim$ 6 MHz) sky in preparation for several upcoming lunar-based…

Astrophysics of Galaxies · Physics 2023-03-29 Neil Bassett , David Rapetti , Bang D. Nhan , Brent Page , Jack O. Burns , Marc Pulupa , Stuart D. Bale

We investigate the parameters of global solar p-mode oscillations, namely damping width $\Gamma$, amplitude $A$, mean squared velocity $\langle v^2\rangle$, energy $E$, and energy supply rate $\mathrm{d}E/\mathrm{d} t$, derived from two…

Solar and Stellar Astrophysics · Physics 2018-10-23 René Kiefer , Rudi Komm , Frank Hill , Anne-Marie Broomhall , Markus Roth

To adequately constrain the frequency of energy deposition in active region cores in the solar corona, systematic comparisons between detailed models and observational data are needed. In this paper, we describe a pipeline for forward…

Solar and Stellar Astrophysics · Physics 2019-07-31 W. T. Barnes , S. J. Bradshaw , N. M. Viall
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