The Solar Origin of Particle Events Measured by Parker Solar Probe

Kouloumvakos, A.; Vourlidas, A.; Rouillard, A. P.; Roelof, E. C.; Leske, R. A.; Pinto, Rui; Poirier, Nicolas

doi:10.3847/1538-4357/aba5a1

Cited by 7 publications

(8 citation statements)

References 41 publications

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“…However, this eruption more closely resembles that of event 1, with a small jet of material and no clear EUV bubble or wave. It is very similar to the eruptions related to the events of 2019 April 2-4 as described in Leske et al (2020) and Kouloumvakos et al (2020). Overall, the basic difference in the size of the eruptions may explain the difference in size of the six SEP events; however, it is not clear how it relates to the compositional differences.…”

Section: Solar Source Regions and Eruptionssupporting

confidence: 79%

Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au

Cohen

Christian

Cummings

et al. 2021

A&A

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Aims. The Parker Solar Probe (PSP) orbit provides an opportunity to study the inner heliosphere at distances closer to the Sun than previously possible. Due to the solar minimum conditions, the initial orbits of PSP yielded only a few solar energetic particle (SEP) events for study. Recently during the fifth orbit, at distances from 0.45 to 0.3 au, the energetic particle suite on PSP, Integrated Science Investigation of the Sun (IS⊙IS), observed a series of six SEP events, adding to the limited number of SEP events studied inside of 0.5 au. Variations in the H and He spectra and the He/H abundance ratio are examined and discussed in relation to the identified solar source regions and activity. Methods. IS⊙IS measures the energetic particle environment from ~20 keV to >100 MeV/nuc. Six events were selected using the ~1 MeV proton intensities, and while small, they were sufficient to calculate proton and helium spectra from ~1 to ~10 MeV/nuc. For the three larger events, the He/H ratio as a function of energy was determined. Using the timing of the associated radio bursts, solar sources were identified for each event and the eruptions were examined in extreme ultraviolet emission. Results. The largest of the selected events has peak ~1 MeV proton intensities of 3.75 (cm2 sr s MeV)−1. Within uncertainties, the He and H spectra have similar power law forms with indices ranging from −2.3 to −3.3. For the three largest events, the He/H ratios are found to be relatively energy independent; however, the ratios differ substantially with values of 0.0033 ± 0.0013, 0.177 ± 0.047, and 0.016 ± 0.009. An additional compositional variation is evident in both the 3He and electron signatures. These variations are particularly interesting as the three larger events are likely a result of similar eruptions from the same active region.

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Section: Solar Source Regions and Eruptionssupporting

confidence: 79%

Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au

Cohen

Christian

Cummings

et al. 2021

A&A

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“…Such reconfiguration is also accompanied by radio bursts and energetic particle acceleration, with at least one energetic particle event seen by IS IS, on 4 Apr. 2019, attributed to this type of process (Leske et al 2020;Kouloumvakos et al 2020).…”

Section: Active Region Sourcesmentioning

confidence: 99%

Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum

et al. 2023

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Launched on 12 Aug. 2018, NASA’s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission’s primary science goal is to determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number of discoveries reported in nearly 700 peer-reviewed publications. The first four years of the 7-year primary mission duration have been mostly during solar minimum conditions with few major solar events. Starting with orbit 8 (i.e., 28 Apr. 2021), Parker flew through the magnetically dominated corona, i.e., sub-Alfvénic solar wind, which is one of the mission’s primary objectives. In this paper, we present an overview of the scientific advances made mainly during the first four years of the Parker Solar Probe mission, which go well beyond the three science objectives that are: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles.

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“…The shock strength (e.g., the Mach number) at these regions can be significantly enhanced (Rouillard et al 2016). Additionally, efficient ion acceleration at the shock wave is expected to take place at these regions (Afanasiev et al 2018;Kouloumvakos et al 2019Kouloumvakos et al , 2020a. The shock wave at these locations is supercritical and strong, and therefore it is expected that a significant portion of the upstream ions can be injected into the acceleration process.…”

Section: Shock Modelling In 3dmentioning

confidence: 99%

The first widespread solar energetic particle event of solar cycle 25 on 2020 November 29

Kouloumvakos

Kwon

Rodríguez-García

et al. 2022

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Context. On 2020 November 29, an eruptive event occurred in an active region located behind the eastern solar limb as seen from Earth. The event consisted of an M4.4 class flare, a coronal mass ejection, an extreme ultraviolet (EUV) wave, and a white-light (WL) shock wave. The eruption gave rise to the first widespread solar energetic particle (SEP) event of solar cycle 25, which was observed at four widely separated heliospheric locations (∼230°). Aims. Our aim is to better understand the source of this widespread SEP event, examine the role of the coronal shock wave in the wide distribution of SEPs, and investigate the shock wave properties at the field lines magnetically connected to the spacecraft. Methods. Using EUV and WL data, we reconstructed the global three-dimensional structure of the shock in the corona and computed its kinematics. We determined the magnetic field configurations in the corona and interplanetary space, inferred the magnetic connectivity of the spacecraft with the shock surface, and derived the evolution of the shock parameters at the connecting field lines. Results. Remote sensing observations show formation of the coronal shock wave occurring early during the eruption, and its rapid propagation to distant locations. The results of the shock wave modelling show multiple regions where a strong shock has formed and efficient particle acceleration is expected to take place. The pressure/shock wave is magnetically connected to all spacecraft locations before or during the estimated SEP release times. The release of the observed near-relativistic electrons occurs predominantly close to the time when the pressure/shock wave connects to the magnetic field lines or when the shock wave becomes supercritical, whereas the proton release is significantly delayed with respect to the time when the shock wave becomes supercritical, with the only exception being the proton release at the Parker Solar Probe. Conclusions. Our results suggest that the shock wave plays an important role in the spread of SEPs. Supercritical shock regions are connected to most of the spacecraft. The particle increase at Earth, which is barely connected to the wave, also suggests that the cross-field transport cannot be ignored. The release of energetic electrons seems to occur close to the time when the shock wave connects to, or becomes supercritical at, the field lines connecting to the spacecraft. Energetic protons are released with a time-delay relative to the time when the pressure/shock wave connects to the spacecraft locations. We attribute this delay to the time that it takes for the shock wave to accelerate protons efficiently.

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The Solar Origin of Particle Events Measured by Parker Solar Probe

Cited by 7 publications

References 41 publications

Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au

Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au

Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum

The first widespread solar energetic particle event of solar cycle 25 on 2020 November 29

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