Observations of Extremely 3He-Rich Solar Energetic Particle Events from Parker Solar Probe

R. A. Leske; E. R. Christian; C. M.S. Cohen; A. C. Cummings; A. J. Davis; G. A. de Nolfo; M. I. Desai; J. Giacalone; M. E. Hill; A. W. Labrador; D. J. McComas; R. L. McNutt; R. A. Mewaldt; D. G. Mitchell; J. G. Mitchell; J. S. Rankin; N. A. Schwadron; T. Sharma; M. M. Shen; J. R. Szalay; M. E. Wiedenbeck; A. Vourlidas; S. D. Bale; M. Pulupa; J. C. Kasper; D. E. Larson; P. Whittlesey

Observations of Extremely ³He-Rich Solar Energetic Particle Events from Parker Solar Probe

R. A. Leske, E. R. Christian, C. M.S. Cohen, A. C. Cummings, A. J. Davis, G. A. de Nolfo, M. I. Desai, J. Giacalone, M. E. Hill, A. W. Labrador, D. J. McComas, R. L. McNutt, R. A. Mewaldt, D. G. Mitchell, J. G. Mitchell, J. S. Rankin, N. A. Schwadron, T. Sharma, M. M. Shen, J. R. SzalayM. E. Wiedenbeck, A. Vourlidas, S. D. Bale, M. Pulupa, J. C. Kasper, D. E. Larson, P. Whittlesey

Research output: Contribution to journal › Conference article › peer-review

Abstract

Since its launch in 2018, the Integrated Science Investigation of the Sun (IS☉IS) instrument suite on Parker Solar Probe has observed numerous periods of ³He-rich solar energetic particle (SEP) events. Notable among them are some very small events that occurred on 21 January 2021 and 30 May 2022, in both cases when Parker was within 0.2 AU of the Sun. In these events the ³He/⁴He ratio was greater than 10 at ∼1 MeV/nucleon but rapidly decreased with increasing energy since ³He had softer spectra than ⁴He. Although unusual, similar extreme enrichments of ³He have occasionally been observed at 1 AU in other events. The events seen by Parker were anisotropic, had velocity dispersion yielding inferred pathlengths longer than expected for scatter-free transport along a nominal Parker spiral, and were associated with type III radio emission detected by Parker/FIELDS. We present the Parker observations of the time profiles, spectra, composition, velocity dispersion, and anisotropies of these events and compare them with previous ³He-rich SEP events detected much farther from the Sun.

Original language	English (US)
Article number	1251
Journal	Proceedings of Science
Volume	444
State	Published - Sep 27 2024
Event	38th International Cosmic Ray Conference, ICRC 2023 - Nagoya, Japan Duration: Jul 26 2023 → Aug 3 2023

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Leske, R. A., Christian, E. R., Cohen, C. M. S., Cummings, A. C., Davis, A. J., de Nolfo, G. A., Desai, M. I., Giacalone, J., Hill, M. E., Labrador, A. W., McComas, D. J., McNutt, R. L., Mewaldt, R. A., Mitchell, D. G., Mitchell, J. G., Rankin, J. S., Schwadron, N. A., Sharma, T., Shen, M. M., ... Whittlesey, P. (2024). Observations of Extremely ³He-Rich Solar Energetic Particle Events from Parker Solar Probe. Proceedings of Science, 444, Article 1251.

Leske, RA, Christian, ER, Cohen, CMS, Cummings, AC, Davis, AJ, de Nolfo, GA, Desai, MI, Giacalone, J, Hill, ME, Labrador, AW, McComas, DJ, McNutt, RL, Mewaldt, RA, Mitchell, DG, Mitchell, JG, Rankin, JS, Schwadron, NA, Sharma, T, Shen, MM, Szalay, JR, Wiedenbeck, ME, Vourlidas, A, Bale, SD, Pulupa, M, Kasper, JC, Larson, DE & Whittlesey, P 2024, 'Observations of Extremely ³He-Rich Solar Energetic Particle Events from Parker Solar Probe', Proceedings of Science, vol. 444, 1251.

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title = "Observations of Extremely 3He-Rich Solar Energetic Particle Events from Parker Solar Probe",

abstract = "Since its launch in 2018, the Integrated Science Investigation of the Sun (IS☉IS) instrument suite on Parker Solar Probe has observed numerous periods of 3He-rich solar energetic particle (SEP) events. Notable among them are some very small events that occurred on 21 January 2021 and 30 May 2022, in both cases when Parker was within 0.2 AU of the Sun. In these events the 3He/4He ratio was greater than 10 at ∼1 MeV/nucleon but rapidly decreased with increasing energy since 3He had softer spectra than 4He. Although unusual, similar extreme enrichments of 3He have occasionally been observed at 1 AU in other events. The events seen by Parker were anisotropic, had velocity dispersion yielding inferred pathlengths longer than expected for scatter-free transport along a nominal Parker spiral, and were associated with type III radio emission detected by Parker/FIELDS. We present the Parker observations of the time profiles, spectra, composition, velocity dispersion, and anisotropies of these events and compare them with previous 3He-rich SEP events detected much farther from the Sun.",

author = "Leske, {R. A.} and Christian, {E. R.} and Cohen, {C. M.S.} and Cummings, {A. C.} and Davis, {A. J.} and {de Nolfo}, {G. A.} and Desai, {M. I.} and J. Giacalone and Hill, {M. E.} and Labrador, {A. W.} and McComas, {D. J.} and McNutt, {R. L.} and Mewaldt, {R. A.} and Mitchell, {D. G.} and Mitchell, {J. G.} and Rankin, {J. S.} and Schwadron, {N. A.} and T. Sharma and Shen, {M. M.} and Szalay, {J. R.} and Wiedenbeck, {M. E.} and A. Vourlidas and Bale, {S. D.} and M. Pulupa and Kasper, {J. C.} and Larson, {D. E.} and P. Whittlesey",

note = "Publisher Copyright: {\textcopyright} Copyright owned by the author(s) under the terms of the Creative Commons.; 38th International Cosmic Ray Conference, ICRC 2023 ; Conference date: 26-07-2023 Through 03-08-2023",

year = "2024",

month = sep,

day = "27",

language = "English (US)",

volume = "444",

journal = "Proceedings of Science",

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TY - JOUR

T1 - Observations of Extremely 3He-Rich Solar Energetic Particle Events from Parker Solar Probe

AU - Leske, R. A.

AU - Christian, E. R.

AU - Cohen, C. M.S.

AU - Cummings, A. C.

AU - Davis, A. J.

AU - de Nolfo, G. A.

AU - Desai, M. I.

AU - Giacalone, J.

AU - Hill, M. E.

AU - Labrador, A. W.

AU - McComas, D. J.

AU - McNutt, R. L.

AU - Mewaldt, R. A.

AU - Mitchell, D. G.

AU - Mitchell, J. G.

AU - Rankin, J. S.

AU - Schwadron, N. A.

AU - Sharma, T.

AU - Shen, M. M.

AU - Szalay, J. R.

AU - Wiedenbeck, M. E.

AU - Vourlidas, A.

AU - Bale, S. D.

AU - Pulupa, M.

AU - Kasper, J. C.

AU - Larson, D. E.

AU - Whittlesey, P.

PY - 2024/9/27

Y1 - 2024/9/27

N2 - Since its launch in 2018, the Integrated Science Investigation of the Sun (IS☉IS) instrument suite on Parker Solar Probe has observed numerous periods of 3He-rich solar energetic particle (SEP) events. Notable among them are some very small events that occurred on 21 January 2021 and 30 May 2022, in both cases when Parker was within 0.2 AU of the Sun. In these events the 3He/4He ratio was greater than 10 at ∼1 MeV/nucleon but rapidly decreased with increasing energy since 3He had softer spectra than 4He. Although unusual, similar extreme enrichments of 3He have occasionally been observed at 1 AU in other events. The events seen by Parker were anisotropic, had velocity dispersion yielding inferred pathlengths longer than expected for scatter-free transport along a nominal Parker spiral, and were associated with type III radio emission detected by Parker/FIELDS. We present the Parker observations of the time profiles, spectra, composition, velocity dispersion, and anisotropies of these events and compare them with previous 3He-rich SEP events detected much farther from the Sun.

AB - Since its launch in 2018, the Integrated Science Investigation of the Sun (IS☉IS) instrument suite on Parker Solar Probe has observed numerous periods of 3He-rich solar energetic particle (SEP) events. Notable among them are some very small events that occurred on 21 January 2021 and 30 May 2022, in both cases when Parker was within 0.2 AU of the Sun. In these events the 3He/4He ratio was greater than 10 at ∼1 MeV/nucleon but rapidly decreased with increasing energy since 3He had softer spectra than 4He. Although unusual, similar extreme enrichments of 3He have occasionally been observed at 1 AU in other events. The events seen by Parker were anisotropic, had velocity dispersion yielding inferred pathlengths longer than expected for scatter-free transport along a nominal Parker spiral, and were associated with type III radio emission detected by Parker/FIELDS. We present the Parker observations of the time profiles, spectra, composition, velocity dispersion, and anisotropies of these events and compare them with previous 3He-rich SEP events detected much farther from the Sun.

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M3 - Conference article

AN - SCOPUS:85212259299

SN - 1824-8039

VL - 444

JO - Proceedings of Science

JF - Proceedings of Science

M1 - 1251

T2 - 38th International Cosmic Ray Conference, ICRC 2023

Y2 - 26 July 2023 through 3 August 2023

ER -

Observations of Extremely ³He-Rich Solar Energetic Particle Events from Parker Solar Probe

Abstract

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