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The theoretical oscillation frequencies of even the best asteroseismic models of solar-like oscillators show significant differences from observed oscillation frequencies. Structure inversions seek to use these frequency differences to…

Solar and Stellar Astrophysics · Physics 2024-02-02 Lynn Buchele , Earl P. Bellinger , Saskia Hekker , Sarbani Basu , Warrick Ball , Jørgen Christensen-Dalsgaard

Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles. Aims. We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes. Methods. A first-order…

Solar and Stellar Astrophysics · Physics 2020-08-05 C. R. Goddard , A. C. Birch , D. Fournier , L. Gizon

The Rapid Oscillations in the Solar Atmosphere (ROSA) instrument reveals solar atmospheric fluctuations at high frequencies. Spectra of variations of the G-band intensity (IG) and CaII K-line intensity (IK) show correlated fluctuations…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. K. Lawrence , A. C. Cadavid , D. J. Christian , D. B. Jess , M. Mathioudakis

The unsigned mean magnetic field characterizes the magnetic energy settled in the region near the solar surface. It is one of the determinant ingredients that govern the turbulence in the photosphere, and the magnetic heating of upper…

Astrophysics · Physics 2007-05-23 P. A. P. Nghiem , R. A. Garcia , S. J. Jimenez-Reyes

Observations of the Sun with the LOWL instrument provide a homogeneous set of solar p-mode frequencies from low to intermediate degree which allows one to determine the structure of much of the solar interior avoiding systematic errors that…

The change of sound speed has been found at the base of the convection during the solar cycles, which can be used to constrain the solar internal magnetic field. We aim to check whether the magnetic field generated by the solar dynamo can…

Solar and Stellar Astrophysics · Physics 2021-06-02 Shaolan Bi , Tanda Li , Kang Liu , Jie Jiang , Yaguang Li , Jinghua Zhang , Xianfei Zhang , Yaqian Wu

$PSP$ and $SolO$ data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency $(20-100d_{i})$ is observed to radially strengthen when methods relying on higher-order moments are considered…

We present an attempt to reconcile the solar tachocline glitch, a thin layer immediately beneath the convection zone in which the seismically inferred sound speed in the Sun exceeds corresponding values in standard solar models, with a…

Solar and Stellar Astrophysics · Physics 2018-04-04 J. Christensen-Dalsgaard , D. O. Gough , E. Knudstrup

The daily measurements of the disc-integrated solar radio flux, observed by the Radio Solar Telescope Network (RSTN), at 245, 410, 610, 1415, 2695, 4995, and 8800 MHz during the time interval of 1989 January 1 to 2019 December 17, are used…

Solar and Stellar Astrophysics · Physics 2024-11-28 N. B. Xiang , X. H. Zhao , L. H. Deng , F. Y. Li , Y. J. Wang , X. W. Tan

Helioseismic observations have detected small temporal variations of the rotation rate below the solar surface corresponding to the so-called `torsional oscillations' known from Doppler measurements of the surface. These appear as bands of…

We have used observations made with the helioseismic instrument LOWL collected over $\sim$ 6 years to carry out an independent study of the variations of the p-mode damping and excitation rates with solar activity. We observe significant…

Astrophysics · Physics 2008-11-26 D. Salabert , S. J. Jiménez-Reyes

We argue that a variety of solar data suggest that the activity-cycle timescale variability of the total irradiance, is produced by structural adjustments of the solar interior. Assuming these adjustments are induced by variations of…

Astrophysics · Physics 2009-10-31 L. H. Li , S. Sofia

The total solar irradiance (TSI) varies on timescales of minute to centuries. On short timescales it varies due to the superposition of intensity fluctuations produced by turbulent convection and acoustic oscillations. On longer scale…

Solar and Stellar Astrophysics · Physics 2022-10-12 V. Penza , F. Berrilli , L. Bertello , M. Cantoresi , S. Criscuoli , P. Giobbi

We have used data collected by the Birmingham Solar-Oscillations Network (BiSON) to perform a helioseismic diagnosis of changes to the Sun's internal structure between four successive solar cycle minima, beginning with the minimum at the…

Solar and Stellar Astrophysics · Physics 2026-02-10 Sarbani Basu , William J. Chaplin , Rachel Howe , Yvonne Elsworth , Steven J. Hale , Eleanor Murray

Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that…

Solar and Stellar Astrophysics · Physics 2014-11-20 Charles S. Baldner , H. M. Antia , Sarbani Basu , T. P. Larson

Here we report in depth reanalysis of a paper by Vats et al. (2001) [Astrophys. J. 548, L87] based on the measurements of differential rotation with altitude as a function of observing frequencies (as lower and higher frequencies indicate…

Solar and Stellar Astrophysics · Physics 2017-02-28 Hitaishi Bhatt , Rupal Trivedi , Som Kumar Sharma , Hari Om Vats

Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to…

Astrophysics · Physics 2009-11-11 J. Christensen-Dalsgaard

The effects of both density stratification and magnetic field expansion on torsional Alfven waves in solar spicules are studied. Also, their eigenfrequencies, eigenfunctions, and the period ratio P_1/P_2 are obtained with a novel…

Solar and Stellar Astrophysics · Physics 2015-06-19 Hossein Ebadi , Sadagat Shahmorad

Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. R. G. Santos , M. S. Cunha , J. J. G. Lima

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