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Related papers: Ion Charge States in a Time-Dependent Wave-Turbule…

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We analyze proton bulk parameters derived from Ulysses observations and investigate the polytropic behavior of solar wind protons over a wide range of heliocentric distances and latitudes. The large-scale variations of the proton density…

Space Physics · Physics 2023-05-10 Georgios Nicolaou , George Livadiotis , David J. McComas

Wave-particle instabilities driven by departures from local thermodynamic equilibrium have been conjectured to play a role in governing solar wind dynamics. We calculate the statistical variation of linear stability over a large subset of…

Solar and Stellar Astrophysics · Physics 2020-01-08 Kristopher G. Klein , Mihailo Martinovic , David Stansby , Timothy S. Horbury

By performing an ensemble of molecular dynamics simulations, the model-dependent ionisation state is computed for strongly interacting systems self-consistently. This is accomplished through a free energy minimisation framework based on the…

Linear theory is a well developed framework for characterizing instabilities in weakly collisional plasmas, such as the solar wind. In the previous instalment of this series, we analyzed ~1.5M proton and alpha particle Velocity Distribution…

Solar and Stellar Astrophysics · Physics 2023-07-26 Mihailo M. Martinovic , Kristopher G. Klein

Current sheets (CSs) are preferred sites of magnetic reconnection and energy dissipation in collisionless astrophysical plasmas. Electric currents in them may be carried by both electrons and ions. In our prior theoretical studies of…

Solar and Stellar Astrophysics · Physics 2022-07-20 Olga Khabarova , Jörg Büchner , Neeraj Jain , Timothy Sagitov , Helmi Malova , Roman Kislov

Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: weakness of collisional dissipation and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Olga Alexandrova , Christopher H. K. Chen , Luca Sorriso-Valvo , Timothy S. Horbury , Stuart D. Bale

Aims: Investigate/Study de-charging of solar wind C, N, O, Mg, Si and S ions and assess fluxes of resulting ENA in the heliosphere. Methods: The model treats the heavy ions as test particles convected by (and in a particular case also…

Astrophysics · Physics 2015-05-13 S. Grzedzielski , M. E. Wachowicz , M. Bzowski , V. Izmodenov

The solar wind plasma is a fully ionized and turbulent gas ejected by the outer layers of the solar corona at very high speed, mainly composed by protons and electrons, with a small percentage of helium nuclei and a significantly lower…

Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for non-thermal features to survive, which suggests…

Space Physics · Physics 2017-05-19 Daniel Verscharen , Christopher H. K. Chen , Robert T. Wicks

The heliosphere is predominantly a partially ionized plasma that consists of electrons, ions and significant neutral atoms. Nonlinear interactions amongst these species take place through direct collision or charge exchange processes. These…

Space Physics · Physics 2015-05-20 M. E. Kellum , Dastgeer Shaikh

Analysis of ion-kinetic instabilities in solar wind plasmas is crucial for understanding energetics and dynamics throughout the heliosphere, as evident from spacecraft observations of complex ion velocity distribution functions (VDFs) and…

Solar and Stellar Astrophysics · Physics 2025-05-27 Viacheslav M Sadykov , Leon Ofman , Scott A Boardsen , Yogesh , Parisa Mostafavi , Lan K Jian , Kristopher Klein , Mihailo Martinović

We perform a statistical assessment of solar wind stability at 1 AU against ion sources of free energy using Nyquist's instability criterion. In contrast to typically employed threshold models which consider a single free-energy source,…

Space Physics · Physics 2018-06-13 K. G. Klein , B. A. Alterman , M. L. Stevens , D. Vech , J. C. Kasper

To predict line emission in the solar atmosphere requires models which are fundamentally different depending on whether the emission is from the chromosphere or the corona. At some point between the two regions, there must be a change…

Solar and Stellar Astrophysics · Physics 2021-03-03 R. P. Dufresne , G. Del Zanna , N. R. Badnell

An approximate method for solving the rate equations for the hydrogen populations was extended and implemented in the three-dimensional radiation (magneto-)hydrodynamics code CO5BOLD. The method is based on a model atom with six energy…

Astrophysics · Physics 2009-11-11 Jorrit Leenaarts , Sven Wedemeyer-Boehm

Solar wind ion reflection at collisionless shocks regulates foreshock plasma dynamics, yet the quantitative dependence of reflected ion properties on upstream and shock-related parameters remains unclear, causing difficulties in predicting…

Space Physics · Physics 2026-03-30 Runyi Liu , Terry Liu , Kun Zhang , Vassilis Angelopoulos , Siqi Zhao

A nonlinear time dependent fluid simulation model is developed that describes the evolution of magnetohydrodynamic waves in the presence of collisional and charge exchange interactions of a partially ionized plasma. The partially ionized…

Space Physics · Physics 2015-05-19 Dastgeer Shaikh , G. P. Zank

A likely candidate mechanism to heat the solar corona and solar wind is low-frequency "Alfv\'enic" turbulence sourced by magnetic fluctuations near the solar surface. Depending on its properties, such turbulence can heat different species…

Solar and Stellar Astrophysics · Physics 2024-09-17 Jonathan Squire , Romain Meyrand , Matthew W. Kunz

The temperature and density conditions in the magnetized photosphere and chromosphere of the Sun lead to a very small degree of atomic ionization. In addition, at particular height, the magnetic field may be strong enough to give rise to a…

Solar and Stellar Astrophysics · Physics 2015-04-08 Elena Khomenko

Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet, mass-loading the solar wind through an effective conversion of fast light solar wind ions into slow heavy cometary ions.…

We propose a new method to estimate ion escape from unmagnetized planets that combines observations and models. Assuming that upstream solar wind conditions are known, a computer model of the interaction between the solar wind and the…

Earth and Planetary Astrophysics · Physics 2022-02-01 M. Holmstrom