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Related papers: 3D propagation of relativistic solar protons throu…

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Solar energetic particles (SEPs), accelerated during solar eruptions, propagate in turbulent solar wind before being observed with in situ instruments. In order to interpret their origin through comparison with remote-sensing observations…

Solar and Stellar Astrophysics · Physics 2020-01-08 T. Laitinen , S. Dalla

We study how a high-speed solar wind stream embedded in a slow solar wind affects the transport and energy changes of solar energetic protons in interplanetary space, assuming different levels of cross-field diffusion. This is done using a…

Space Physics · Physics 2020-01-08 Nicolas Wijsen , Angels Aran , Jens Pomoell , Stefaan Poedts

We report that the number of > 500 MeV protons (Ng) inferred from sustained gamma ray emission (SGRE) from the Sun is significantly correlated with that of protons propagating into space (NSEP) as solar energetic particles (SEPs). Under the…

Solar and Stellar Astrophysics · Physics 2021-07-21 N. Gopalswamy , S. Yashiro , P. Makela , H. Xie , S. Akiyama

This paper investigates the onset time of Solar Energetic Particle (SEP) events with numerical simulations, and analyses the accuracy of the Velocity Dispersion Analysis (VDA) method. Using a 3-dimensional focused transport model, we…

Solar and Stellar Astrophysics · Physics 2015-06-18 Y. Wang , G. Qin

The acceleration of protons and electrons to high (sometimes GeV/nucleon) energies by solar phenomena is a key component of space weather. These solar energetic particle (SEP) events can damage spacecraft and communications, as well as…

Solar energetic particles (SEPs) affect the solar-terrestrial space environment and become a very important aspect in space weather research. In this work, we numerically investigate the transport processes of SEPs in three-dimensional…

Solar and Stellar Astrophysics · Physics 2015-06-04 H. -Q. He , W. Wan

Context. The intensity profiles of iron and oxygen in Solar Energetic Particle (SEP) events often display differences that result in a decreasing Fe/O ratio over time. The physical mechanisms behind this behaviour are not fully understood,…

Solar and Stellar Astrophysics · Physics 2017-02-08 S. Dalla , M. S. Marsh , P. Zelina , T. Laitinen

Aims. We investigated the transport of solar energetic particles (SEPs) during the relativistic widespread event of 28 October 2021, quantifying the role of parallel and perpendicular diffusion and constraining the spatial extent of the…

Solar and Stellar Astrophysics · Physics 2026-03-11 E. Lavasa , J. T. Lang , A. Papaioannou , R. D. Strauss , S. A. Mallios , A. Hillaris , A. Kouloumvakos , A. Anastasiadis , I. A. Daglis

On 2017 September 10 Neutron Monitors (NMs) apparatus located at ground level and high latitudes detected an increase in the counting rate associated to solar energetic particles (SEPs) emission from X8.2-class solar flare and its…

Solar and Stellar Astrophysics · Physics 2018-12-19 C. R. A. Augusto , C. E. Navia , M. N. de Oliveira , A. A. Nepomuceno , A. C. Fauth , V. Kopenkin , T. Sinzi

High-energy particles were recorded by near-Earth spacecraft and ground-based neutron monitors (NMs) on 2012 May 17. This event was the first ground level enhancement (GLE) of solar cycle 24. In this study, we try to identify the…

Solar and Stellar Astrophysics · Physics 2013-05-27 C. Li , Kazi A. Firoz , L. P. Sun , L. I. Miroshnichenko

The processes responsible for the effective longitudinal transport of solar energetic particles (SEPs) are still not completely understood. We address this issue by simulating SEP electron propagation using a spatially 2D transport model…

Solar and Stellar Astrophysics · Physics 2018-04-12 R. D. Strauss , N. Dresing , N. E. Engelbrecht

In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well-connected to at least one spacecraft at 1~au. The observed intensity-time profiles, for all available proton…

Solar and Stellar Astrophysics · Physics 2024-06-11 J. T. Lang , R. D. Strauss , N. E. Engelbrecht , J. P. van den Berg , N. Dresing , D. Ruffolo , R. Bandyopadhyay

Solar energetic particles (SEPs) have been observed to easily spread across heliographic longitudes, and the mechanisms responsible for this behaviour remain unclear. We use full-orbit simulations of a 10 MeV proton beam in a turbulent…

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

Solar Energetic Particles (SEPs) are charged particles accelerated within the solar atmosphere or the interplanetary space by explosive phenomena such as solar flares or Coronal Mass Ejections (CMEs). Once injected into the interplanetary…

This paper investigates the conditions for producing rapid variations of solar ener- getic particle (SEP) intensity commonly known as dropouts. In particular, we use numerical model simulations based on solving the focused transport…

Solar and Stellar Astrophysics · Physics 2015-06-19 Y. Wang , G. Qin , M. Zhang , S. Dalla

One of the earliest indicators of the importance of shock acceleration of solar energetic particles (SEPs) was the broad spatial extent of the "gradual" SEP events produced as the shock waves, driven by wide, fast coronal mass ejections…

Solar and Stellar Astrophysics · Physics 2022-08-31 Donald V. Reames

As part of the HESPERIA Horizon 2020 project, we developed a software package for the direct inversion of Ground Level Enhancements (GLEs) based on data of the worldwide network of Neutron Monitors (NMs). The new methodology to study the…

Instrumentation and Methods for Astrophysics · Physics 2016-12-30 Rolf Bütikofer , Neus Agueda , Bernd Heber , Dennis Galsdorf , Rami Vainio

After introduction we focus on: the transport of charged particles, the acceleration of ions at shocks, and the acceleration of electrons at shocks. Chapter 2 studies the propagation of solar energetic particles(SEPs) in turbulent magnetic…

High Energy Astrophysical Phenomena · Physics 2012-11-16 Fan Guo

Intense solar energetic particle (SEP) events data, associated with ground level enhancements (GLEs), occurred during 1989 to 2006 have been obtained from the spectrometers on board GOES spacecraft in the energy range 10-100 MeV. The…

Solar and Stellar Astrophysics · Physics 2017-08-02 P. K. Manoharan , G. Agalya

Solar Energetic Particles (SEPs) are a signature of solar eruptions, and to link them to acceleration mechanisms many studies investigate their injection time at the Sun, $t_{sun}$. We assess velocity dispersion analysis (VDA), an…

Solar and Stellar Astrophysics · Physics 2026-03-09 T. Laitinen , S. Dalla