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Related papers: A transonic collisionless model of the solar wind

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In the solar corona and solar wind, electron heat conduction is an important process that transports energy over large distances and helps determine the spatial variation of temperature. High-density regions undergoing rapid…

Solar and Stellar Astrophysics · Physics 2021-11-03 Steven R. Cranmer , Avery J. Schiff

We analyze measured proton and electron temperatures in the high-speed solar wind in order to calculate the separate rates of heat deposition for protons and electrons. When comparing with other regions of the heliosphere, the fast solar…

Solar and Stellar Astrophysics · Physics 2015-05-13 Steven R. Cranmer , William H. Matthaeus , Benjamin A. Breech , Justin C. Kasper

The solar corona has been revealed in the past decade to be a highly dynamic nonequilibrium plasma environment. Both the loop-filled coronal base and the extended acceleration region of the solar wind appear to be strongly turbulent, but…

Astrophysics · Physics 2008-11-26 Steven R. Cranmer

We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and…

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 aim at analytically modelling the solar wind proton trajectories during their interaction with a partially ionised cometary atmosphere, not in terms of bulk properties of the flow but in terms of single particle dynamics. We first derive…

Earth and Planetary Astrophysics · Physics 2018-11-28 E. Behar , B. Tabone , M. Saillenfest , P. Henri , J. Deca , J. Lindkvist , M. Holmström , H. Nilsson

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

A model is presented for generation of fast solar wind in coronal holes, relying on heating that is dominated by turbulent dissipation of MHD fluctuations transported upwards in the solar atmosphere. Scale-separated transport equations…

Solar and Stellar Astrophysics · Physics 2015-05-14 A. Verdini , M. Velli , W. H. Matthaeus , S. Oughton , P. Dmitruk

By comparing a magneto-frictional model of the low coronal magnetic field to a potential-field source-surface model, we investigate the possible impact of non-potential magnetic structure on empirical solar-wind models. These empirical…

Solar and Stellar Astrophysics · Physics 2015-12-09 S. J. Edwards , A. R. Yeates , F. -X. Bocquet , D. H. Mackay

Plasma in the Sun's hot corona expands into the heliosphere as a supersonic and highly magnetized solar wind. This paper provides an overview of our current understanding of how the corona is heated and how the solar wind is accelerated.…

Solar and Stellar Astrophysics · Physics 2015-08-19 S. R. Cranmer , M. Asgari-Targhi , M. P. Miralles , J. C. Raymond , L. Strachan , H. Tian , L. N. Woolsey

(abridged) We investigate how the properties of the corona and solar wind in the open coronal holes depend on the properties of the magnetic fields and their footpoint motions at the surface, by perfoming 1D MHD simulations from the…

Astrophysics · Physics 2015-06-24 Takeru K. Suzuki , Shu-ichiro Inutsuka

In situ measurements of kinetic scale current sheets in the solar wind show that they are often approximately force-free although the plasma beta is of order one. They frequently display systematic asymmetric and anti-correlated spatial…

Solar and Stellar Astrophysics · Physics 2025-09-30 Sophie Boswell , Thomas Neukirch , Anton Artemyev , Ivan Vasko , Oliver Allanson

The lower solar atmosphere is an intrinsically multi-component and collisional environment with electron and proton collision frequencies in the range $10^{8}-10^{10}$ Hz, which may be considerably higher than the gyro-frequencies for both…

Solar and Stellar Astrophysics · Physics 2013-06-04 J. Vranjes , P. S. Krstic

Collisionless shocks are loosely defined as shocks where the transition between pre-and post-shock states happens on a length scale much shorter than the collisional mean free path. In the absence of collision to enforce thermal equilibrium…

Astrophysics of Galaxies · Physics 2015-06-16 Parviz Ghavamian , Steven J. Schwartz , Jeremy Mitchell , Adam Masters , J. Martin Laming

Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized ambient medium, these shocks can transfer energy to particles.…

Although it is widely accepted that photospheric motions provide the energy source and that the magnetic field must play a key role in the process, the detailed mechanisms responsible for heating the Sun's corona and accelerating the solar…

Solar and Stellar Astrophysics · Physics 2016-01-12 Roberto Lionello , Marco Velli , Cooper Downs , Jon A. Linker , Zoran Mikić

This paper reviews our growing understanding of the physics behind coronal heating (in open-field regions) and the acceleration of the solar wind. Many new insights have come from the last solar cycle's worth of observations and theoretical…

Solar and Stellar Astrophysics · Physics 2010-02-02 Steven R. Cranmer , John L. Kohl , Mari Paz Miralles , Adriaan A. van Ballegooijen

We have performed a 2.5 dimensional magnetohydrodynamic simulation that resolves the propagation and dissipation of Alfven waves in the solar atmosphere. Alfvenic fluctuations are introduced on the bottom boundary of the extremely large…

Solar and Stellar Astrophysics · Physics 2015-06-18 Takuma Matsumoto , Takeru K. Suzuki

We develop a 1D solar-wind model that includes separate energy equations for the electrons and protons, proton temperature anisotropy, collisional and collisionless heat flux, and an analytical treatment of low-frequency, reflection-driven,…

Solar and Stellar Astrophysics · Physics 2012-01-10 Benjamin D. G. Chandran , Timothy J. Dennis , Eliot Quataert , Stuart D. Bale