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Related papers: The visibility of low-frequency solar acoustic mod…

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Recent observations indicate that solar p-mode line profiles are not exactly Lorentzian, but rather exhibit varying amounts of asymmetry about their respective peaks. We analyze p-mode line asymmetry using both a simplified one-dimensional…

Astrophysics · Physics 2007-05-23 Pawan Kumar , Douglas Abrams

We explore the sensitivity of the frequencies of low-degree solar p-modes to near-surface magnetic flux on different spatial scales and strengths, specifically to active regions with strong magnetic fields and ephemeral regions with weak…

Variations of frequency separations of low-degree p-modes are studied over the solar activity cycle. The separations studied are obtained from the frequencies of low-degree p-modes of the Global Oscillation Network Group (GONG). 10.7 cm…

Solar and Stellar Astrophysics · Physics 2015-05-14 Wuming Yang , Xiangcun Meng

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

The amplitude of solar p-mode oscillations is governed by stochastic excitation and mode damping, both of which take place in the surface convection zone. However, the time-dependent, turbulent nature of convection makes it difficult to…

Solar and Stellar Astrophysics · Physics 2019-07-24 Yixiao Zhou , Martin Asplund , Remo Collet

We used long duration, high quality, unresolved (Sun-as-a star) observations collected by the ground based network BiSON and by the instruments GOLF and VIRGO on board the ESA/NASA SOHO satellite to search for solar-cycle-related changes in…

Solar and Stellar Astrophysics · Physics 2010-04-21 R. Simoniello , W. Finsterle , R. A. Garcia , D. Salabert , A. Jimenez , Y. Elsworth , H. Schunker

According to a recent ray-based asymptotic theory, the high-frequency p-mode spectrum of rapidly rotating stars is a superposition of frequency subsets associated with dynamically independent regions of the ray-dynamics phase space. At high…

Solar and Stellar Astrophysics · Physics 2015-05-20 F. Lignieres , B. Georgeot , J. Ballot

We used the m-averaged spectrum technique ("collapsogram") to extract the low-frequency solar p-mode parameters of low- and intermediate-angular degrees (l \leq 35) in long time series of GONG and MDI observations. Rotational splittings and…

Astrophysics · Physics 2008-11-12 D. Salabert , A. Eff-Darwich , R. Howe , S. G. Korzennik

A review on acoustic mode damping and excitation in solar-type stars is presented. Current models for linear damping rates are discussed in the light of recent low-degree solar linewidth measurements with emphasis on the…

Astrophysics · Physics 2007-05-23 G. Houdek

Frequency and rotational splittings of the solar f-modes are estimated from the GONG data. Contrary to earlier observations the frequencies of f-modes are found to be close to the theoretically computed values for a standard solar model.…

Astrophysics · Physics 2008-11-26 H. M. Antia

The characteristic of the solar acoustic spectrum is such that mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases for a given order. A direct consequence of this property is that…

Astrophysics · Physics 2009-11-07 S. G. Korzennik , M. C. Rabello-Soares , J. Schou

Solar twins have been a focus of attention for more than a decade, because their structure is extremely close to that of the Sun. Today, thanks to high-precision spectrometers, it is possible to use asteroseismology to probe their…

We establish that global solar p-mode frequencies can be measured with sufficient precision on time scales as short as nine days to detect activity-related shifts. Using ten years of GONG data, we report that mode-mass and error-weighted…

Astrophysics · Physics 2009-02-10 S. C. Tripathy , F. Hill , K. Jain , J. W. Leibacher

Solar p-mode oscillations are excited by the work of stochastic, non-adiabatic, pressure fluctuations on the compressive modes. We evaluate the expression for the radial mode excitation rate derived by Nordlund and Stein (Paper I) using…

Astrophysics · Physics 2009-10-31 R. F. Stein , Å. Nordlund

We suggest a solution to an important problem of observational helioseismology of the separation of lines of solar acoustic (p) modes of low angular degree in oscillation power spectra by constructing optimal masks for Doppler images of the…

Astrophysics · Physics 2009-10-31 T. Toutain , A. G. Kosovichev

The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations…

Solar and Stellar Astrophysics · Physics 2015-06-04 Anne-Marie Broomhall , David Salabert , William J. Chaplin , Rafael A. Garcia , Yvonne Elsworth , Rachel Howe , Savita Mathur

The quest of the knowledge of the structure and dynamics of the solar interior has been possible thanks to the study of the resonant acoustic (p) modes that are trapped in the solar interior. Since the solar rotation lifts the azimuthal…

Astrophysics · Physics 2008-11-03 R. A. Garcia

In the case of spatially-revolved helioseismic data (such as MDI, GONG, HMI), the usual mode-fitting analysis consists of fitting the 2l+1 individual m-spectra of a given multiplet (n, l) either individually or simultaneously. Such fitting…

Astrophysics · Physics 2008-10-13 D. Salabert , R. A. Garcia

In this paper, we investigate the performance of energy detection-based spectrum sensing over F composite fading channels. To this end, an analytical expression for the average detection probability is firstly derived. This expression is…

Signal Processing · Electrical Eng. & Systems 2018-07-18 Seong Ki Yoo , Simon L. Cotton , Paschalis C. Sofotasios , Sami Muhaidat , Osamah S. Badarneh , George K. Karagiannidis

Normal-mode coupling is a technique applied to probe the solar interior using surface observations of oscillations. The technique, which is straightforward to implement, makes more use of the seismic information in the wavefield than other…

Solar and Stellar Astrophysics · Physics 2021-04-14 Chris S. Hanson , Shravan Hanasoge , Katepalli R. Sreenivasan