scholarly journals Numerical MHD Simulations of the 3D Morphology and Kinematics of the 2017 September 10 CME-driven Shock from the Sun to Earth

2021 ◽  
Vol 918 (1) ◽  
pp. 31
Author(s):  
Liping Yang ◽  
Haopeng Wang ◽  
Xueshang Feng ◽  
Ming Xiong ◽  
Man Zhang ◽  
...  
Keyword(s):  
The Sun ◽  
Mhd Simulations ◽  
3D Morphology

scholarly journals Evolution of the 12 July 2012 CME from the Sun to the Earth: Data-constrained three-dimensional MHD simulations

2014 ◽  
Vol 119 (9) ◽  
pp. 7128-7141 ◽  
Author(s):  
Fang Shen ◽  
Chenglong Shen ◽  
Jie Zhang ◽  
Phillip Hess ◽  
Yuming Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
The Sun ◽  
Mhd Simulations ◽  
The Earth

Study of starspots in fully convective stars using three dimensional MHD simulations

2018 ◽  
Vol 13 (S340) ◽  
pp. 303-304
Author(s):  
Arnab Basak ◽  
Dibyendu Nandy
Keyword(s):  
High Resolution ◽  
Numerical Simulations ◽  
High Latitude ◽  
Three Dimensional ◽  
Stellar Dynamics ◽  
The Sun ◽  
Dynamo Action ◽  
Magnetic Structures ◽  
Mhd Simulations ◽  
Self Consistent

AbstractConcentrated magnetic structures such as sunspots and starspots play a fundamental role in driving solar and stellar activity. However, as opposed to the sun, observations as well as numerical simulations have shown that stellar spots are usually formed as high-latitude patches extended over wide areas. Using a fully spectral magnetohydrodynamic (MHD) code, we simulate polar starspots produced by self-consistent dynamo action in rapidly rotating convective shells. We carry out high resolution simulations and investigate various properties related to stellar dynamics which lead to starspot formation.

scholarly journals Reconstruction of the Parker spiral with the Reverse In situ data and MHD APproach - RIMAP

2020 ◽  
Author(s):  
Ruggero Biondo ◽  
Alessandro Bemporad ◽  
Andrea Mignone ◽  
Fabio Reale
Keyword(s):  
Interplanetary Medium ◽  
Small Scale ◽  
Reconstruction Technique ◽  
The Sun ◽  
Plasma Parameters ◽  
In Situ Data ◽  
Mhd Simulations ◽  
Solar Eruptions ◽  
In Situ Observations

The reconstruction of plasma parameters in the interplanetary medium is very important to understand the interplanetary propagation of solar eruptions and for Space Weather application purposes. Because only a few spacecraft are measuring in situ these parameters, reconstructions are currently performed by running complex numerical Magneto-hydrodynamic (MHD) simulations starting from remote sensing observations of the Sun. Current models apply full 3D MHD simulations of the corona or extrapolations of photospheric magnetic fields combined with and semiempirical relationships to derive the plasma parameters on a sphere centered on the Sun (inner boundary). The plasma is then propagated in the interplanetary medium up to the Earth’s orbit and beyond. Nevertheless, this approach requires significant theoretical and computational efforts, and the results are only in partial agreement with the in situ observations. In this paper we describe a new approach to this problem called RIMAP - Reverse In situ data and MHD APproach. The plasma parameters in the inner boundary at 0.1 AU are derived directly from the in situ measurements acquired at 1 AU, by applying a back reconstruction technique to remap them into the inner heliosphere. This remapping is done by using the Weber and Davies solar wind theoretical model to reconstruct the wind flowlines. The plasma is then re-propagated outward from 0.1 AU by running a MHD numerical simulation based on the PLUTO code. The interplanetary spiral reconstructions obtained with RIMAP are not only in a much better agreement with the in situ observations, but are also including many more small-scale longitudinal features in the plasma parameters that are not reproduced with the approaches developed so far.

scholarly journals Magnetohydrodynamic study on the effect of the gravity stratification on flux rope ejections

2013 ◽  
Vol 8 (S300) ◽  
pp. 197-200
Author(s):  
Paolo Pagano ◽  
Duncan H. Mackay ◽  
Stefaan Poedts
Keyword(s):  
Free Field ◽  
Flux Rope ◽  
Decisive Role ◽  
Propagation Speed ◽  
The Sun ◽  
Magnetic Structures ◽  
Mhd Simulations ◽  
Linear Force ◽  
Force Free Field ◽  
Solar Gravity

AbstractCoronal Mass Ejections (CMEs) are one of the most violent phenomena found on the Sun. One model to explain their occurrence is the flux rope ejection model where these magnetic structures firt form in the solar corona then are ejected to produce a CME. We run simulations coupling two models. The Global Non-Linear Force-Free Field (GNLFFF) evolution model to follow the quasi-static formation of a flux rope and MHD simulations for the production of a CME through the loss of equilibrium and ejection of this flux rope in presence of solar gravity and density stratification. Our realistic multi-beta simulations describe the CME following the flux rope ejection and highlight the decisive role played by the gravity stratification on the CME propagation speed.

scholarly journals Modeling solar wind mass-loading in the vicinity of the Sun using 3-D MHD simulations

2014 ◽  
Vol 119 (1) ◽  
pp. 18-25 ◽  
Author(s):  
A. P. Rasca ◽  
M. Horányi ◽  
R. Oran ◽  
B. van der Holst
Keyword(s):  
Solar Wind ◽  
The Sun ◽  
Mass Loading ◽  
Mhd Simulations

Chromospheric activity as a function of age in main-sequence stars

1966 ◽  
Vol 24 ◽  
pp. 40-43
Author(s):  
O. C. Wilson ◽  
A. Skumanich
Keyword(s):  
Main Sequence ◽  
The Sun ◽  
Main Sequence Stars ◽  
Tentative Conclusion ◽  
Chromospheric Activity ◽  
General Field ◽  
Large Clusters

Evidence previously presented by one of the authors (1) suggests strongly that chromospheric activity decreases with age in main sequence stars. This tentative conclusion rests principally upon a comparison of the members of large clusters (Hyades, Praesepe, Pleiades) with non-cluster objects in the general field, including the Sun. It is at least conceivable, however, that cluster and non-cluster stars might differ in some fundamental fashion which could influence the degree of chromospheric activity, and that the observed differences in chromospheric activity would then be attributable to the circumstances of stellar origin rather than to age.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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