Monte Carlo simulations of a diffusive shock with multiple scattering angular distributions

Wang, X.; Yan, Yihua

doi:10.1051/0004-6361/201116791

Cited by 13 publications

(19 citation statements)

References 45 publications

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“…In this scattering scenario, the assumption of elastic scattering requires that scattering centers are frozen into the background fluid. Simultaneously, the assumption of a constant collision time for all particles requires that the particle's mean free path is proportional to its local thermal velocity in the local frame (Knerr et al 1996;Wang & Yan 2011Wang et al 2013;Ellsion et al 2016). For simplicity, we take its formula as…”

Section: Modelmentioning

confidence: 99%

Particle Acceleration at the Pileup Collision of the Twin Shock

Wang

Giacalone

Yan

et al. 2019

ApJ

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Ground-level enhancement (GLE) events are often associated with large gradual solar events such as fast coronal mass ejections (CMEs), but not all fast CMEs lead to GLE events. Is there a type of coordinated CME that could produce GLEs with larger intensity and higher energies than those in the normal fast isolated CMEs? Here we propose a twin-shock scenario driven by the twin CME coordinately, in which the posterior shock catches up with the preceding shock and has a pileup collision. In the present study, we chose the first GLE event of the solar cycle 24 occurring on 2012 May 17 as an example to investigate the probable association with the twin-shock scenario. We use a dynamic Monte Carlo method to examine the energy spectrum with relevance to the GLE event. In the twin-shock scenario, the seed energetic particles produced by the normal preceding shock can be injected into the posterior shock for reacceleration efficiently. As a result, we obtain the detailed energy spectrum of the solar energetic particles (SEPs) with different behaviors at the related episodes of the twin-shock evolution. Therefore, we predict that the pileup collision of the twin shock would dominate a concave energy spectral slope in the 2012 May 17 SEP event.

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Section: Modelmentioning

confidence: 99%

Particle Acceleration at the Pileup Collision of the Twin Shock

Wang

Giacalone

Yan

et al. 2019

ApJ

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“…However, the extensive energy spectra for resolving issues such as the energy spectral "break" are not easy to obtain. Nevertheless, the Monte Carlo method (Ellison & Eichler 1984;Wang & Yan 2011;Wang et al 2013) solves the Boltzmann equation using the collective scattering technique, replacing the explicit calculation of the electromagnetic field in the shock region. The scattering mean free path is assumed to be a function of the particle rigidity.…”

Section: Introductionmentioning

confidence: 99%

Particle Acceleration in Two Converging Shocks^∗

Wang

Giacalone

Yan

et al. 2017

ApJ

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Observations by spacecraft such as ACE, STEREO, and others show that there are proton spectral "breaks" with energy E br at 1-10 MeV in some large CME-driven shocks. Generally, a single shock with the diffusive acceleration mechanism would not predict the "broken" energy spectrum. The present paper focuses on two converging shocks to identify this energy spectral feature. In this case, the converging shocks comprise one forward CME-driven shock on 2006 December 13 and another backward Earth bow shock. We simulate the detailed particle acceleration processes in the region of the converging shocks using the Monte Carlo method. As a result, we not only obtain an extended energy spectrum with an energy "tail" up to a few 10 MeV higher than that in previous single shock model, but also we find an energy spectral "break" occurring on ∼5.5 MeV. The predicted energy spectral shape is consistent with observations from multiple spacecraft. The spectral "break," then, in this case is caused by the interaction between the CME shock and Earth's bow shock, and otherwise would not be present if Earth were not in the path of the CME.

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“…Therefore, the energy spectral "break" would form at a certain energy point between 1-10MeV. The specific observed parameters and the simulated parameters can be referenced as to the related literatures [12,13,11,14,15]. The thick solid line with a narrow peak at E = 1.43keV represents the initial Maxwellian energy distribution in the upstream region.…”

Section: Pos(icrc2017)102mentioning

confidence: 99%

“…Both of them have a great advantage in that they determine the self-generated magnetic turbulence self-consistently, but the extensive energy spectra are not easy to obtain for resolving the issues such as energy spectral "break". Nevertheless, the Monte Carlo method [4,12,11] solves the Boltzman equation using collective scattering technique, replacing of the explicit calculation of the electromagnetic field in the shock region. The scattering mean free path is assumed to be a function of the particle rigidity.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the energy spectra between single shock and converging double-shock

Wang¹,

Yin²,

Ding³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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Observations show that there are proton spectral "breaks" with energy E br at 1-10MeV in some large solar energetic particle (SEP) events. Generally, single CME-driven shock applying diffusive acceleration mechanism would just predict a single power-law energy spectrum. This work discusses the difference of the energy spectra between a single shock and the converging doubleshock. We apply a single shock and a converging double-shock models to the 2006 Dec 13 SEP event using particle simulation method, respectively. As results, we find that a single shock model just produce an energy spectrum with a single-power law, but a double converging-shock model can produce a "broken" energy spectrum splitting to double power-law, which is consistent with the observed energy spectrum by spacecraft.

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Monte Carlo simulations of a diffusive shock with multiple scattering angular distributions

Cited by 13 publications

References 45 publications

Particle Acceleration at the Pileup Collision of the Twin Shock

Particle Acceleration at the Pileup Collision of the Twin Shock

Particle Acceleration in Two Converging Shocks^∗

Comparison of the energy spectra between single shock and converging double-shock

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Monte Carlo simulations of a diffusive shock with multiple scattering angular distributions

Cited by 13 publications

References 45 publications

Particle Acceleration at the Pileup Collision of the Twin Shock

Particle Acceleration at the Pileup Collision of the Twin Shock

Particle Acceleration in Two Converging Shocks∗

Comparison of the energy spectra between single shock and converging double-shock

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Product

Resources

About

Particle Acceleration in Two Converging Shocks^∗