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Oscillations are abundant in the solar corona. Coronal loop oscillations are typically studied using highly idealised models of magnetic flux tubes. In order to improve our understanding of coronal oscillations, it is necessary to consider…

Solar and Stellar Astrophysics · Physics 2023-08-02 P. Kohutova , P. Antolin , M. Szydlarski , M. Carlsson

This report presents a three-dimensional (3D) numerical magnetohydrodynamics (MHD) model of the white-light coronagraph observational phenomena known as coronal inflows and in/out pairs. Coronal inflows in the LASCO/C2 field of view…

Solar and Stellar Astrophysics · Physics 2020-12-23 Benjamin J. Lynch

The temporal covariance between seismic waves measured at two locations on the solar surface is the fundamental observable in time-distance helioseismology. Above the acoustic cut-off frequency ($\sim$5.3~mHz), waves are not trapped in the…

Solar and Stellar Astrophysics · Physics 2017-12-13 Damien Fournier , Michael Leguebe , Chris S. Hanson , Laurent Gizon , Helene Barucq , Juliette Chabassier , Marc Durufle

As the solar wind propagates through the heliosphere, dynamical processes irreversibly erase the signatures of the near-Sun heating and acceleration processes. The elemental fractionation of the solar wind should not change during transit…

Solar and Stellar Astrophysics · Physics 2020-08-11 D. Stansby , D. Baker , D. H. Brooks , C. J. Owen

Characterising the large-scale structure and plasma properties of the inner corona is crucial to understand the source and subsequent expansion of the solar wind and related space weather effects. Here we apply a new coronal rotational…

Solar and Stellar Astrophysics · Physics 2020-04-22 Huw Morgan , Anthony C. Cook

Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy…

Solar and Stellar Astrophysics · Physics 2017-08-09 R. Lionello , T. TÖrÖk , V. S. Titov , J. E. Leake , Z. MikiĆ , J. A. Linker , M. G. Linton

The high-speed solar wind is typically the simplest and least stochastic type of large-scale plasma flow in the heliosphere. For much of the solar cycle, it is connected magnetically to large polar coronal holes on the Sun's surface.…

Solar and Stellar Astrophysics · Physics 2020-12-22 Steven R. Cranmer

We present a method to derive outflow velocities in the solar corona using different data sets including solar wind mass flux coming from the SWAN/SOHO instrument, electron density values from LASCO-C2 and interplanetary solar wind…

Astrophysics · Physics 2009-11-13 E. Quemerais , R. Lallement , D. Koutroumpa , P. Lamy

Observations of surface magnetic fields are now within reach for many stellar types thanks to the development of Zeeman-Doppler Imaging. These observations are extremely useful for constraining rotational evolution models of stars, as well…

Solar and Stellar Astrophysics · Physics 2015-09-24 Victor Réville , Allan Sacha Brun , Antoine Strugarek , Sean P. Matt , Jérôme Bouvier , Colin P. Folsom , Pascal Petit

The proton temperature anisotropy in the solar wind exhibits apparent bounds which are compatible with the theoretical constraints imposed by temperature-anisotropy driven kinetic instabilities. Recent statistical analyses based on…

Space Physics · Physics 2014-09-12 Petr Hellinger , Pavel M. Travnicek

We derive a simple analytical model for the propagation of HSSs from the Sun to Earth and thereby show how the area of coronal holes and the size of their boundary regions affect the HSS velocity, temperature, and density near Earth. We…

In this paper we seek to understand the timescale on which the photospheric motions on the Sun braid coronal magnetic field lines. This is a crucial ingredient for determining the viability of the braiding mechanism for explaining the high…

Solar and Stellar Astrophysics · Physics 2018-09-19 Simon Candelaresi , David Pontin , Anthony Yeates , Paul Bushby , Gunnar Hornig

The pressure and energy density of the gas and magnetic field inside solar coronal mass ejections (in relation to that in the ambient solar wind) is thought to play an important role in determining their dynamics as they propagate through…

Although the mechanisms responsible for heating the Sun's corona and accelerating the solar wind are still being actively investigated, it is largely accepted that photospheric motions provide the energy source and that the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-06-18 Roberto Lionello , Marco Velli , Cooper Downs , Jon A. Linker , Zoran Mikić , Andrea Verdini

We undertake a first attempt towards a consistent reconstruction of the coronal magnetic field and the coronal density structure. We consider a stationary solar corona which has to obey the equations of magnetohydrostatics. We solve these…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , B. Inhester

The solar wind speed at 1 AU shows variations in latitude and in time which reflect the evolution of the global background magnetic field during the activity cycle. It is commonly accepted that the terminal wind speed in a magnetic…

Solar and Stellar Astrophysics · Physics 2016-07-27 R. F. Pinto , A. S. Brun , A. P. Rouillard

This article discusses the magnetic connectivity between the Sun and the Earth, which is essential for understanding solar wind and space weather events. Due to limited direct observations, reliable simulations are necessary. The most…

Solar and Stellar Astrophysics · Physics 2024-11-20 Silke Kennis , Barbara Perri , Stefaan Poedts

We present a new model, MULTI-VP, that computes the three-dimensional structure of the solar wind which includes the chromosphere, the transition region, and the corona and low heliosphere. MULTI-VP calculates a large ensemble of wind…

Solar and Stellar Astrophysics · Physics 2017-04-05 Rui F. Pinto , Alexis P. Rouillard

The ambient solar wind plays a significant role in propagating interplanetary coronal mass ejections and is an important driver of space weather geomagnetic storms. A computationally efficient and widely used method to predict the ambient…

Space Physics · Physics 2023-09-21 Opal Issan , Pete Riley , Enrico Camporeale , Boris Kramer

A semi-empirical, axisymmetric model of the solar minimum corona is developed by solving the equations for conservation of mass and momentum with prescribed anisotropic temperature distributions. In the high-latitude regions, the proton…

Astrophysics · Physics 2009-11-10 Alberto M. Vasquez , Adriaan A. van Ballegooijen , John C. Raymond