Z. G. Xu, C. M. S Cohen, R. A. Leske, G. D. Muro, A. C. Cummings, D. J. McComas, N. A. Schwadron, E. R. Christian, M. E. Wiedenbeck, R. L. McNutt, D. G. Mitchell, G. M. Mason, A. Kouloumvakos, R. F. Wimmer-Schweingruber, G. C. Ho and J. Rodriguez-Pacheco
{"title":"SolO 和 PSP 观测到的 2023 年 5 月 16 日太阳高能粒子事件的成分变化","authors":"Z. G. Xu, C. M. S Cohen, R. A. Leske, G. D. Muro, A. C. Cummings, D. J. McComas, N. A. Schwadron, E. R. Christian, M. E. Wiedenbeck, R. L. McNutt, D. G. Mitchell, G. M. Mason, A. Kouloumvakos, R. F. Wimmer-Schweingruber, G. C. Ho and J. Rodriguez-Pacheco","doi":"10.3847/2041-8213/ad8b18","DOIUrl":null,"url":null,"abstract":"In this study, we employ the combined charged particle measurements from Integrated Science Investigation of the Sun on board the Parker Solar Probe (PSP) and Energetic Particle Detector on board the Solar Orbiter (SolO) to study the composition variation of the solar energetic particle (SEP) event occurring on 2023 May 16. During the event, SolO and PSP were located at a similar radial distance of ∼0.7 au and were separated by ∼60° in longitude. The footpoints of both PSP and SolO were west of the flare region, but the former was much closer (18° versus 80°). Such a distribution of observers is ideal for studying the longitudinal dependence of the ion composition with the minimum transport effects of particles along the radial direction. We focus on H, He, O, and Fe measured by both spacecraft in sunward and antisunward directions. Their spectra are in a double power-law shape, which is fitted best by the Band function. Notably, the event was Fe rich at PSP, where the mean Fe/O ratio at energies of 0.1–10 Mev nuc−1 was 0.48, higher than the average Fe/O ratio in previous large SEP events. In contrast, the mean Fe/O ratio at SolO over the same energy range was considerably lower at 0.08. The Fe/O ratio between 0.5 and 10 MeV nuc−1 at both spacecraft is nearly constant. Although the He/H ratio shows energy dependence, decreasing with increasing energy, the He/H ratio at PSP is still about twice as high as that at SolO. Such a strong longitudinal dependence of element abundances and the Fe-rich component in the PSP data could be attributed to the direct flare contribution. Moreover, the temporal profiles indicate that differences in the Fe/O and He/H ratios between PSP and SolO persisted throughout the entire event rather than only at the start.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"35 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Composition Variation of the 2023 May 16 Solar Energetic Particle Event Observed by SolO and PSP\",\"authors\":\"Z. G. Xu, C. M. S Cohen, R. A. Leske, G. D. Muro, A. C. Cummings, D. J. McComas, N. A. Schwadron, E. R. Christian, M. E. Wiedenbeck, R. L. McNutt, D. G. Mitchell, G. M. Mason, A. Kouloumvakos, R. F. Wimmer-Schweingruber, G. C. Ho and J. 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Their spectra are in a double power-law shape, which is fitted best by the Band function. Notably, the event was Fe rich at PSP, where the mean Fe/O ratio at energies of 0.1–10 Mev nuc−1 was 0.48, higher than the average Fe/O ratio in previous large SEP events. In contrast, the mean Fe/O ratio at SolO over the same energy range was considerably lower at 0.08. The Fe/O ratio between 0.5 and 10 MeV nuc−1 at both spacecraft is nearly constant. Although the He/H ratio shows energy dependence, decreasing with increasing energy, the He/H ratio at PSP is still about twice as high as that at SolO. Such a strong longitudinal dependence of element abundances and the Fe-rich component in the PSP data could be attributed to the direct flare contribution. 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引用次数: 0
摘要
在这项研究中,我们利用帕克太阳探测器(Parker Solar Probe,PSP)和太阳轨道器(Solar Orbiter,SolO)上的高能粒子探测器(Energetic Particle Detector,SolO)对太阳的综合科学探测(Integrated Science Investigation of the Sun)的带电粒子测量数据,研究了2023年5月16日发生的太阳高能粒子(SEP)事件的成分变化。在事件发生期间,太阳轨道器和高能粒子探测器的径向距离相近,均为∼0.7 au,经度相隔∼60°。PSP和SolO的脚点都在耀斑区以西,但前者更近(18°对80°)。这样的观测点分布非常适合研究离子组成的纵向依赖性,粒子沿径向的传输影响最小。我们重点研究了两个航天器在向阳和反向测量到的 H、He、O 和 Fe。它们的光谱呈双幂律形状,与 Band 函数的拟合效果最佳。值得注意的是,该事件的PSP富含铁,在能量为0.1-10 Mev nuc-1时,Fe/O比率平均值为0.48,高于以往大型SEP事件的Fe/O比率平均值。相比之下,相同能量范围内 SolO 的平均 Fe/O 比率要低得多,仅为 0.08。两个航天器在 0.5 到 10 MeV nuc-1 之间的 Fe/O 比率几乎是恒定的。虽然 He/H 比值与能量有关,随着能量的增加而降低,但 PSP 的 He/H 比值仍然是 SolO 的两倍。PSP 数据中的元素丰度和富铁成分具有如此强的纵向依赖性,可能是由于耀斑的直接贡献。此外,时间剖面图表明,PSP 和 SolO 的 Fe/O 和 He/H 比率差异持续存在于整个事件中,而不仅仅是在事件开始时。
Composition Variation of the 2023 May 16 Solar Energetic Particle Event Observed by SolO and PSP
In this study, we employ the combined charged particle measurements from Integrated Science Investigation of the Sun on board the Parker Solar Probe (PSP) and Energetic Particle Detector on board the Solar Orbiter (SolO) to study the composition variation of the solar energetic particle (SEP) event occurring on 2023 May 16. During the event, SolO and PSP were located at a similar radial distance of ∼0.7 au and were separated by ∼60° in longitude. The footpoints of both PSP and SolO were west of the flare region, but the former was much closer (18° versus 80°). Such a distribution of observers is ideal for studying the longitudinal dependence of the ion composition with the minimum transport effects of particles along the radial direction. We focus on H, He, O, and Fe measured by both spacecraft in sunward and antisunward directions. Their spectra are in a double power-law shape, which is fitted best by the Band function. Notably, the event was Fe rich at PSP, where the mean Fe/O ratio at energies of 0.1–10 Mev nuc−1 was 0.48, higher than the average Fe/O ratio in previous large SEP events. In contrast, the mean Fe/O ratio at SolO over the same energy range was considerably lower at 0.08. The Fe/O ratio between 0.5 and 10 MeV nuc−1 at both spacecraft is nearly constant. Although the He/H ratio shows energy dependence, decreasing with increasing energy, the He/H ratio at PSP is still about twice as high as that at SolO. Such a strong longitudinal dependence of element abundances and the Fe-rich component in the PSP data could be attributed to the direct flare contribution. Moreover, the temporal profiles indicate that differences in the Fe/O and He/H ratios between PSP and SolO persisted throughout the entire event rather than only at the start.