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Related papers: Spreading protons in the heliosphere: a note on cr…

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The event-averaged charge state of heavy ion Solar Energetic Particles (SEPs), measured at 1 AU from the Sun, typically increases with the ions' kinetic energy. The origin of this behaviour has been ascribed to processes taking place within…

Space Physics · Physics 2017-02-08 S. Dalla , M. S. Marsh , M. Battarbee

We study the EUV/soft X-ray emission generated by charge transfer between solar wind heavy ions and interstellar H and He neutral atoms in the inner Heliosphere. We present heliospheric maps and spectra for stationary solar wind, depending…

Insights into the processes of Solar Energetic Particle (SEP) propagation are essential for understanding how solar eruptions affect the radiation environment of near-Earth space. SEP propagation is influenced by turbulent magnetic fields…

Solar and Stellar Astrophysics · Physics 2018-01-11 T. Laitinen , F. Effenberger , A. Kopp , S. Dalla

Drifts in the Parker spiral interplanetary magnetic field are known to be an important component in the propagation of galactic cosmic rays, while they are thought to be negligible for Solar Energetic Particles (SEPs). As a result they have…

Solar and Stellar Astrophysics · Physics 2013-10-08 S. Dalla , M. S. Marsh , J. Kelly , T. Laitinen

Solar wind stream interaction regions (SIRs) are often characterized by energetic ion enhancements. The mechanisms accelerating these particles, as well as the locations where the acceleration occurs, remain debated. Here, we report the…

Space Physics · Physics 2021-02-23 Nicolas Wijsen , Evangelia Samara , Àngels Aran , David Lario , Jens Pomoell , Stefaan Poedts

One of the basic properties of the solar wind, that is the high speed of the fast wind, is still not satisfactorily explained. This is mainly due to the theoretical difficulty of treating weakly collisional plasmas. The fluid approach…

Astrophysics · Physics 2009-11-11 I. Zouganelis , N. Meyer-Vernet , S. Landi , M. Maksimovic , F. Pantellini

A complete theory for the complex interaction between solar energetic particles and the turbulent interplanetary magnetic field remains elusive. In this work we aim to contribute towards such a theory by modelling the propagation of solar…

Space Physics · Physics 2019-02-27 R. D. Strauss , J. A. le Roux

The propagation of solar energetic particles (SEPs) through the heliosphere is primarily guided by the interplanetary magnetic field (IMF) which is embedded in the solar wind plasma. Large-scale IMF structures can drive transient variations…

The Solar Wind Electrons Alphas and Protons experiment on the Parker Solar Probe (PSP) mission measures the three-dimensional electron velocity distribution function. We derive the parameters of the core, halo, and strahl populations…

The relationship between the peak velocities of high-speed solar wind streams near Earth and the areas of their solar source regions, i.e., coronal holes, has been known since the 1970s, but it is still physically not well understood. We…

Solar and Stellar Astrophysics · Physics 2020-07-10 Stefan J. Hofmeister , Astrid M. Veronig , Stefaan Poedts , Evangelia Samara , Jasmina Magdalenic

In this work, a gradual solar energetic particle (SEP) event observed by multispacecraft has been simulated. The time profiles of SEP fluxes accelerated by an interplanetary shock in the three-dimensional interplanetary space are obtained…

Solar and Stellar Astrophysics · Physics 2015-09-09 G. Qin , Y. Wang

The transport of charged energetic particles in the presence of strong intermittent heliospheric turbulence is computationally analyzed based on known properties of the interplanetary magnetic field and solar wind plasma at 1 Astronomical…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Fathallah Alouani-Bibi , Jakobus A. le Roux

The slow solar wind is generally believed to result from the interaction of open and closed coronal magnetic flux at streamers and pseudostreamers. We use 3-dimensional magnetohydrodynamic simulations to determine the detailed structure and…

Solar and Stellar Astrophysics · Physics 2022-05-11 V. Aslanyan , D. I. Pontin , A. K. Higginson , P. F. Wyper , R. B. Scott , S. K. Antiochos

Solar Energetic Particle (SEP) events are critical for understanding particle acceleration and transport in the heliosphere. While most SEP events involve outward streaming particles along open magnetic field lines, bidirectional events…

Using one-dimensional hybrid expanding box model we investigate properties of the solar wind in the outer heliosphere. We assume a proton-electron plasma with a strictly transverse ambient magnetic field and, beside the expansion, we take…

Solar and Stellar Astrophysics · Physics 2016-11-17 Petr Hellinger , Pavel M. Travnicek

We investigate the deceleration of Solar Energetic Particles (SEPs) during their propagation from the Sun through interplanetary space, in the presence of weak to strong scattering in a Parker spiral configuration, using relativistic full…

Solar and Stellar Astrophysics · Physics 2015-08-17 S. Dalla , M. S. Marsh , T. Laitinen

The solar wind undergoes non-adiabatic heating as it travels away from the Sun. The velocity phase space distribution of non-equilibrium ions in the solar wind indicate a source of free energy that could contribute significantly to this…

Because of the semi-collisional nature of the solar wind, the collisionless or exospheric approach as well as the hydrodynamic one are both inaccurate. However, the advantage of simplicity makes them useful for enlightening some basic…

Astrophysics · Physics 2009-11-10 I. Zouganelis , M. Maksimovic , N. Meyer-Vernet , H. Lamy , K. Issautier

Protons in the solar corona and heliosphere exhibit anisotropic velocity distributions, violation of magnetic moment conservation, and a general lack of thermal equilibrium with the other particle species. There is no agreement about the…

Solar and Stellar Astrophysics · Physics 2015-06-19 Steven R. Cranmer

Parker Solar Probe (PSP) observations have revealed that most of the solar wind acceleration occurs very close to the Sun. This acceleration is partly due to the global electric potential originating from the mass disparity between…

Solar and Stellar Astrophysics · Physics 2025-05-14 Maximilien Péters de Bonhome , Viviane Pierrard , Fabio Bacchini