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Related papers: Intensity contrast of the average supergranule

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Observations of the solar surface reveal the presence of flows with length scales of around $35$ Mm, commonly referred to as supergranules. Inferring the sub-surface flow profile of supergranules from measurements of the surface and…

Solar and Stellar Astrophysics · Physics 2016-08-03 Jishnu Bhattacharya , Shravan M. Hanasoge

The effect of the electron density stratification on the intensity profiles of the H I Ly-$\alpha$ line and the O VI and Mg X doublets formed in solar coronal holes is investigated. We employ an analytical 2-D model of the large scale…

Astrophysics · Physics 2007-05-23 N. -E. Raouafi , S. K. Solanki

Luminosity, which is the total amount of radiant energy emitted by an object, is one of the most critical quantities in astrophysics for characterizing stars. Equally important is the temporal evolution of a star's luminosity because of its…

Solar and Stellar Astrophysics · Physics 2022-06-20 L. E. A. Vieira , G. Kopp , T. Dudok de Wit , L. A. da Silva , F. Carlesso , A. Barbosa , A. Muralikrishna , R. Santos

We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale…

Solar and Stellar Astrophysics · Physics 2015-06-22 J. W. Lord , R. H. Cameron , M. P. Rast , M. Rempel , T. Roudier

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…

Solar and Stellar Astrophysics · Physics 2021-10-20 Prasad Mani , Shravan Hanasoge

Stellar variability due to magnetic activity and flows at different spatial scales strongly impacts radial velocities. This variability is seen as oscillations, granulation, supergranulation, and meridional flows. The effect of this latter…

Solar and Stellar Astrophysics · Physics 2020-06-17 Nadège Meunier , Anne-Marie Lagrange

Aims: The interactions of velocity scales on the Sun's surface, from granulation to supergranulation are still not understood, nor are their interaction with magnetic fields. We thus aim at giving a better description of dynamics in the…

Solar and Stellar Astrophysics · Physics 2009-02-16 T. Roudier , M. Rieutord , D. Brito , F. Rincon , J. M. Malherbe , N. Meunier , T. Berger , Z. Frank

Supergranules are believed to be an evidence for large-scale subsurface convection. The vertical component of the supergranular flow field is very hard to measure, but it is considered only a few m/s in and below the photosphere. Here I…

Solar and Stellar Astrophysics · Physics 2013-01-10 Michal Svanda

We resolve the paradox that although magnetic collimation of an isotropic solar wind results in an enhancement of its proton flux along the polar directions, several observations indicate a wind proton flux peaked at the equator. To that…

Astrophysics · Physics 2007-05-23 K. Tsinganos , S. Bogovalov

The meridional circulation at high latitudes is crucial to the build-up and reversal of the Sun's polar magnetic fields. Here we characterize the axisymmetric flows by applying a magnetic feature cross-correlation procedure to high…

Solar and Stellar Astrophysics · Physics 2013-03-26 Lisa Rightmire-Upton , David H. Hathaway , Katie Kosak

We calculate the density contrast of the Shapley Supercluster (SSC) based on the enhanced abundance of X-ray clusters in it using the extended Press-Schechter formalism. We derive a total SSC mass of M_tot=(4.4+-0.44)x10^{16} M_sun within a…

Astrophysics · Physics 2009-11-13 Joseph A. Muñoz , Abraham Loeb

The spatiotemporal inhomogeneous-homogeneous transition in the dynamics and structures of solar photospheric turbulence is studied by applying the complexity-entropy analysis to Hinode images of a vortical region of supergranular junctions…

We analyze and model total solar irradiance variability on time scales from minutes to months, excluding variations due to p-mode oscillations, using a combination of convective and magnetic components. These include granulation, the…

Solar and Stellar Astrophysics · Physics 2013-03-11 Andrey D. Seleznyov , Sami K. Solanki , Natalie A. Krivova

We statistically study the property of emerging flux regions (EFRs) and the upper solar atmosphere response to the flux emergence by using data from the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) on…

Solar and Stellar Astrophysics · Physics 2015-06-05 Jie Zhao , Hui Li

Solar wind turbulence is anisotropic with respect to the mean magnetic field. Anisotropy leads to ambiguity when interpreting in-situ turbulence observations in the solar wind because an apparent change in the measurements could be due…

Solar and Stellar Astrophysics · Physics 2022-01-12 L. -L. Zhao , G. P. Zank , L. Adhikari , M. Nakanotani

Recently, Duvall and Hanasoge ({\it Solar Phys.} {\bf 287}, 71-83, 2013) found that large distance $[\Delta]$ separation travel-time differences from a center to an annulus $[\delta t_{\rm{oi}}]$ implied a model of the average supergranular…

Solar and Stellar Astrophysics · Physics 2015-06-19 T. L. Duvall , S. M. Hanasoge , S. Chakraborty

Differences between observed and theoretical eigenfrequencies of the Sun have characteristics which identify them as arising predominantly from properties of the oscillations in the vicinity of the solar surface: in the super-adiabatic,…

Efforts to understand unusual weather or abrupt changes in climate have been plagued by deficiencies of the standard solar model (SSM). While it assumes that our primary source of energy began as a homogeneous ball of hydrogen (H) with a…

Astrophysics · Physics 2007-05-23 O. Manuel , B. W. Ninham , S. E. Friberg

This paper investigates the conditions for producing rapid variations of solar ener- getic particle (SEP) intensity commonly known as dropouts. In particular, we use numerical model simulations based on solving the focused transport…

Solar and Stellar Astrophysics · Physics 2015-06-19 Y. Wang , G. Qin , M. Zhang , S. Dalla

Kilogauss-strength magnetic fields are often observed in intergranular lanes at the photosphere in the quiet Sun. Such fields are stronger than the equipartition field $B_e$, corresponding to a magnetic energy density that matches the…

Astrophysics · Physics 2009-11-13 P. J. Bushby , S. M. Houghton , M. R. E. Proctor , N. O. Weiss
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