A Self-consistent Simulation of Proton Acceleration and Transport Near a High-speed Solar Wind Stream

Wijsen, Nicolas; Samara, Evangelia; Aran, A.; Lario, D.; Pomoell, Jens; Poedts, Stefaan

doi:10.3847/2041-8213/abe1cb

Cited by 30 publications

(32 citation statements)

References 46 publications

(63 reference statements)

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“…Another point to note is the presence of multiple sector boundary crossings for around a day ahead of the CIR on November 30, including during the early stages of the SEP event, indicating that SolO was close to the heliospheric plasma sheet at this time, with possible implications for SEP transport. Thus, the SolO observations suggest that the arrival of energetic particles at the spacecraft depends on the region where they are accelerated and the influence of solar wind structures on their transport in the inner heliosphere, and that both of these factors depend on the energy of the particles (e.g., Wijsen et al 2021).…”

Section: In Situ Observationsmentioning

confidence: 99%

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Kollhoff¹,

Kouloumvakos²,

Lario³

et al. 2021

A&A

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Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner ( 1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe (PSP), the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near-Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection (CME) and an extreme ultraviolet (EUV) wave as well as a type II radio burst and multiple type III radio bursts. Aims. We present multi-spacecraft particle observations and place them in context with source observations from remote sensing instruments and discuss how such observations may further our understanding of particle acceleration and transport in this widespread event. Methods. Velocity dispersion analysis (VDA) and time shift analysis (TSA) were used to infer the particle release times at the Sun. Solar wind plasma and magnetic field measurements were examined to identify structures that influence the properties of the energetic particles such as their intensity. Pitch angle distributions and first-order anisotropies were analyzed in order to characterize the particle propagation in the interplanetary medium. Results. We find that during the 2020 November 29 SEP event, particles spread over more than 230°in longitude close to 1 AU. The particle onset delays observed at the different spacecraft are larger as the flare-footpoint angle increases and are consistent with those from previous STEREO observations. Comparing the timing when the EUV wave intersects the estimated magnetic footpoints of each spacecraft with particle release times from TSA and VDA, we conclude that a simple scenario where the particle release is only determined by the EUV wave propagation is unlikely for this event. Observations of anisotropic particle distributions at SolO, Wind, and STEREO-A do not rule out that particles are injected over a wide longitudinal range close to the Sun. However, the low values of the first-order anisotropy observed by near-Earth spacecraft suggest that diffusive propagation processes are likely involved.

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Section: In Situ Observationsmentioning

confidence: 99%

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Kollhoff¹,

Kouloumvakos²,

Lario³

et al. 2021

A&A

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“…These measurements, in combination with solar wind plasma and interplanetary magnetic field (IMF) data, are key to understanding the various particle acceleration mechanisms acting in interplanetary (IP) space. For example, Wijsen et al (2021) model the transport and acceleration undergone by the particles responsible for an SIR low-energy proton event on 19 September 2019, observed by both PSP and the Solar Terrestrial Relations Observatory Ahead (STEREO-A) SC, and conclude that the particles were accelerated at the compression waves associated with the observed SIR. On the other hand, Richardson (1985) and Schwadron et al (1996Schwadron et al ( , 2020 analysed other SIR events, showing that second-order Fermi acceleration processes contribute to local ion acceleration in SIRs.…”

Section: Introductionmentioning

confidence: 99%

Evidence for local particle acceleration in the first recurrent galactic cosmic ray depression observed by Solar Orbiter

Aran¹,

Pacheco²,

Laurenza³

et al. 2021

A&A

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Context. In mid-June 2020, the Solar Orbiter (SolO) mission reached its first perihelion at 0.51 au and started its cruise phase, with most of the in situ instruments operating continuously. Aims. We present the in situ particle measurements of the first proton event observed after the first perihelion obtained by the Energetic Particle Detector (EPD) suite on board SolO. The potential solar and interplanetary (IP) sources of these particles are investigated. Methods. Ion observations from ∼20 keV to ∼1 MeV are combined with available solar wind data from the Radio and Plasma Waves (RPW) instrument and magnetic field data from the magnetometer (MAG) on board SolO to evaluate the energetic particle transport conditions and infer the possible acceleration mechanisms through which particles gain energy. We compare > 17 -20 MeV ion count rate measurements for two solar rotations, along with the solar wind plasma data available from the Solar Wind Analyser (SWA) and RPW instruments, in order to infer the origin of the observed galactic cosmic ray (GCR) depressions. Results. The lack of an observed electron event and of velocity dispersion at various low-energy ion channels and the observed IP structure indicate a local IP source for the low-energy particles. From the analysis of the anisotropy of particle intensities, we conclude that the low-energy ions were most likely accelerated via a local second-order Fermi process. The observed GCR decrease on 19 June, together with the 51.8 -1034.0 keV/nuc ion enhancement, was due to a solar wind stream interaction region (SIR). The observation of a similar GCR decrease in the next solar rotation favours this interpretation and constitutes the first observation of a recurrent GCR decrease by SolO. The analysis of the recurrence times of this SIR suggests that it is the same SIR responsible for the 4 He events previously measured in April and May. Finally, we point out that an IP structure more complex than a common SIR cannot be discarded, mainly due to the lack of solar wind temperature measurements and the lack of a higher cadence of solar wind velocity observations.

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“…To model the ESP event with PARADISE, we inject 50 keV protons continuously at the CME-driven shock wave. Similar to Prinsloo et al (2019) and Wijsen et al (2021), the injected particle intensity j inj is scaled as…”

Section: Paradise Set-upmentioning

confidence: 99%

“…EUHFORIA stands for 'EUropean Heliospheric FORcasting Information Asset' and simulates the propagation of the solar wind and CMEs through interplanetary space by solving the ideal MHD equations, using boundary conditions derived from a solar magnetogram in a semi-empirical manner. In Wijsen et al (2021), the EUHFORIA+PARADISE model was used to successfully reproduce an energetic particle event associated with a corotating interaction region (CIR), which was observed in September 2019 by both Parker Solar Probe (PSP) and the Ahead spacecraft of the Solar TErrestrial RElations Observatory (STEREO-A).…”

Section: Introductionmentioning

confidence: 99%

Observation-based modelling of the energetic storm particle event of 14 July 2012

Wijsen

Aran

Scolini

et al. 2022

A&A

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Aims. We model the energetic storm particle (ESP) event of July 14, 2012 using the energetic particle acceleration and transport model named 'PArticle Radiation Asset Directed at Interplanetary Space Exploration' (PARADISE), together with the solar wind and coronal mass ejection (CME) model named 'EUropean Heliospheric FORcasting Information Asset' (EUHFORIA). The simulation results illustrate both the capabilities and limitations of the utilised models. We show that the models capture some essential structural features of the ESP event; however, for some aspects the simulations and observations diverge. We describe and, to some extent, assess the sources of errors in the modelling chain of EUHFORIA and PARADISE, and discuss how they may be mitigated in the future.Methods. The PARADISE model computes energetic particle distributions in the heliosphere by solving the focused transport equation in a stochastic manner. This is done using a background solar wind configuration generated by the ideal MHD module of EUHFORIA. The CME generating the ESP event is simulated by using the spheromak model of EUHFORIA, which approximates the CME by a linear force-free spheroidal magnetic field. In addition, a tool was developed to trace CME-driven shock waves in the EUHFORIA simulation domain. This tool is used in PARADISE to (i) inject 50 keV protons continuously at the CME-driven shock and (ii) include a foreshock and a sheath region, in which the energetic particle parallel mean free path, λ , decreases towards the shock wave. The value of λ at the shock wave is estimated from in-situ observations of the ESP event.Results. For energies below ∼1 MeV, the simulation results agree well with both the upstream and downstream components of the ESP event observed by the Advanced Composition Explorer (ACE). This suggests that these low energy protons are mainly the result of interplanetary particle acceleration. In the downstream region, the sharp drop in the energetic particle intensities is reproduced at the entry into the following magnetic cloud, illustrating the importance of a magnetised CME model.

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A Self-consistent Simulation of Proton Acceleration and Transport Near a High-speed Solar Wind Stream

Cited by 30 publications

References 46 publications

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Evidence for local particle acceleration in the first recurrent galactic cosmic ray depression observed by Solar Orbiter

Observation-based modelling of the energetic storm particle event of 14 July 2012

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