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Meridional circulation is a crucial component of the Sun's internal dynamics, but its inference in the deep interior is complicated by a systematic center-to-limb effect in helioseismic measurement techniques. Previously, an empirical…

太阳与恒星天体物理 · 物理学 2017-11-15 Ruizhu Chen , Junwei Zhao

According to time-distance helioseismology, information about internal fluid motions is encoded in the travel times of solar waves. The inverse problem consists of inferring 3-D vector flows from a set of travel-time measurements. Here we…

太阳与恒星天体物理 · 物理学 2015-05-27 M. Svanda , L. Gizon , S. M. Hanasoge , S. D. Ustyugov

The Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) filtergrams, taken at six wavelengths around the Fe I 6173.3 {\AA} line, contain information about the line-of-sight velocity over a range of heights in the solar…

We study Doppler velocity measurements at multiple heights in the solar atmosphere using a set of six filtergrams obtained by the Helioseismic magnetic Imager on board the Solar Dynamics Observatory. There are clear and significant phase…

太阳与恒星天体物理 · 物理学 2014-01-15 Kaori Nagashima , Laurent Gizon , Aaron Birch , Björn Löptien , Sebastien Couvidat , Bernhard Fleck

In many models used in engineering and science, material properties are uncertain or spatially varying. For example, in geophysics, and porous media flow in particular, the uncertain permeability of the material is modelled as a random…

数值分析 · 数学 2019-07-30 Pieterjan Robbe , Dirk Nuyens , Stefan Vandewalle

The SDO/HMI instruments provide photospheric vector magnetograms with a high spatial and temporal resolution. Our intention is to model the coronal magnetic field above active regions with the help of a nonlinear force-free extrapolation…

太阳与恒星天体物理 · 物理学 2015-06-04 T. Wiegelmann , J. K. Thalmann , B. Inhester , T. Tadesse , X. Sun , J. T. Hoeksema

We implement a Monte Carlo sampling strategy to extract helicity parton densities and their uncertainties from a reference set of longitudinally polarized scattering data, chosen to be that used in the DSSV14 global analysis. Instead of…

高能物理 - 唯象学 · 物理学 2019-12-25 Daniel de Florian , Gonzalo Agustin Lucero , Rodolfo Sassot , Marco Stratmann , Werner Vogelsang

The self-healing diffusion Monte Carlo algorithm (SHDMC) [Reboredo, Hood and Kent, Phys. Rev. B {\bf 79}, 195117 (2009); Reboredo, {\it ibid.} {\bf 80}, 125110 (2009)] is extended to study the ground and excited states of magnetic and…

强关联电子 · 物理学 2011-06-10 Fernando Agustín Reboredo

The Helioseismic and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) observes the Sun at the Fe I 6173 {\AA} line and returns full-disk maps of line-of-sight (LOS) observables including the magnetic flux density,…

太阳与恒星天体物理 · 物理学 2015-02-20 Daniel P. Cohen , Serena Criscuoli , Laurel Farris , Alexandra Tritschler

We present the first accurate characterization of high-degree modes, derived using the best MDI full-disk full-resolution data set available. A ninety day long time series of full-disk two arc-second per pixel resolution dopplergrams was…

太阳与恒星天体物理 · 物理学 2015-06-11 S. G. Korzennik , M. C. Rabello-Soares , J. Schou , T. P. Larson

It is well known that the observed amplitude of solar oscillations is lower in sunspots than in quiet regions of the Sun. We show that this local reduction in oscillation amplitudes combined with the phase-speed filtering procedure in…

天体物理学 · 物理学 2009-11-11 S. P. Rajaguru , A. C. Birch , T. L. Duvall , M. J. Thompson , J. Zhao

Long-lived rotational and meridional flows are important ingredients of the solar cycle. Magnetic field images have typically been used to measure these flows on the solar surface by cross-correlating thin longitudinal strips or square…

太阳与恒星天体物理 · 物理学 2017-02-15 Derek A. Lamb

The solar coronal magnetic field produces solar activity, including extremely energetic solar flares and coronal mass ejections (CMEs). Knowledge of the structure and evolution of the magnetic field of the solar corona is important for…

太阳与恒星天体物理 · 物理学 2015-06-22 Tilaye Tadesse , Thomas Wiegelmann , Peter MacNeice

Helioseismic observations have provided valuable datasets with which to pursue the detailed investigation of solar interior dynamics. Among various methods to analyse these data, normal-mode coupling has proven to be a powerful tool, used…

太阳与恒星天体物理 · 物理学 2021-10-20 Prasad Mani , Shravan Hanasoge

Using solar-cycle long helioseismic measurements of meridional and zonal flows in the near-surface shear layer (NSSL) of the Sun, we study their spatio-temporal variations and connections to active regions. We find that near-surface inflows…

太阳与恒星天体物理 · 物理学 2025-12-16 Anisha Sen , S. P. Rajaguru , Abhinav Govindan Iyer , Ruizhu Chen , Junwei Zhao , Shukur Kholikov

Helioseismology, the study of global solar oscillations, has proved to be an extremely powerful tool for the investigation of the internal structure and dynamics of the Sun. Studies of time changes in frequency observations of solar…

太阳与恒星天体物理 · 物理学 2023-03-15 M. P. Di Mauro

Results of forward modelling of acoustic wave propagation in a realistic solar sub-photosphere with two cases of steady horizontal flows are presented and analysed by the means of local helioseismology. The simulations are based on fully…

天体物理学 · 物理学 2009-11-13 S. Shelyag , R. Erdelyi , M. J. Thompson

We compare measurements of horizontal flows on the surface of the Sun using helioseismic time--distance inversions and coherent structure tracking of solar granules. Tracking provides 2D horizontal flows on the solar surface, whereas the…

太阳与恒星天体物理 · 物理学 2015-06-15 M. Svanda , Th. Roudier , M. Rieutord , R. Burston , L. Gizon

We report our first results on comparing the variations of the solar internal rotation with solar activity, as predicted by non-linear solar dynamo modelling, with helioseismic measurements using the SOHO MDI data.

天体物理学 · 物理学 2007-05-23 S. Vorontsov , R. Tavakol , E. Covas , D. Moss

In the last decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models (SSM) constructed with the new low-metal abundances disagree with helioseismic results and detected…

太阳与恒星天体物理 · 物理学 2016-04-27 Wuming Yang