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A new view of energetic particles from stream interaction regions observed by Parker Solar Probe

Schwadron, N. A. and Joyce, C. J. and Aly, A. and Cohen, C. M. S. and Desai, M. I. and McComas, D. J. and Niehof, J. T. and Möbius, E. and Lee, M. and Bower, J. and Bale, S. and Case, A. and Christian, E. R. and Davis, A. J. and de Wet, W. and Goetz, K. and Giacalone, J. and Hill, M. E. and Allen, R. and Kasper, J. C. and Korreck, K. and Leske, R. A. and Malandraki, O. and Matthaeus, W. H. and McNutt, R. L. and Mewaldt, R. A. and Mitchell, D. G. and Pulupa, M. and Rankin, J. S. and Roelof, E. C. and Stone, E. C. and Szalay, J. R. and Wiedenbeck, M. E. (2021) A new view of energetic particles from stream interaction regions observed by Parker Solar Probe. Astronomy and Astrophysics, 650 . Art. No. A24. ISSN 0004-6361. doi:10.1051/0004-6361/202039352.

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Early observations from the first orbit of Parker Solar Probe (PSP) show recurrent stream interaction regions that form close to the Sun. Energetic particle enhancements were observed on the 320th–326th day of the year 2018, which corresponds to ~1–7 days after the passage of the stream interface between faster and slower solar wind. Energetic particles stream into the inner heliosphere to the PSP spacecraft near 0.33 au (71 solar radii) where they are measured by the Integrated Science Investigation of the Sun (IS⊙IS). The large 6-day time interval over which energetic particles are observed after the stream passage provides a unique perspective on the development of stream interactions within the heliosphere. The long duration of energetic particle enhancements suggests that particles stream in through the inner heliosphere more directly along magnetic field lines that form a sub-Parker spiral structure due to magnetic footpoint motion at the Sun and shearing of the magnetic field in the rarefaction region behind the stream interface. The strong build-up of energetic particle fluxes in the first 3 days after the passage of the stream interface indicates that suprathermal populations are enhanced near the interaction region through compression or other acceleration processes in addition to being diffusively accelerated. The early increases in energetic particle fluxes (in the first 3 days) in the formation of these events allows for the characterization of the acceleration associated with these suprathermal seed populations. Thus, we show that the time history of energetic particle fluxes observed by IS⊙IS provides a new view of particle acceleration at stream interaction regions throughout the inner heliosphere.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemIS⊙IS data and visualization tools ItemNASA Space Physics Data Facility
Schwadron, N. A.0000-0002-3737-9283
Joyce, C. J.0000-0002-3841-5020
Cohen, C. M. S.0000-0002-0978-8127
Desai, M. I.0000-0002-7318-6008
McComas, D. J.0000-0001-6160-1158
Bale, S.0000-0002-1989-3596
Case, A.0000-0002-3520-4041
Christian, E. R.0000-0003-2134-3937
Goetz, K.0000-0003-0420-3633
Giacalone, J.0000-0002-0850-4233
Hill, M. E.0000-0002-5674-4936
Allen, R.0000-0003-2079-5683
Kasper, J. C.0000-0002-7077-930X
Korreck, K.0000-0001-6095-2490
Leske, R. A.0000-0002-0156-2414
Malandraki, O.0000-0002-4751-6835
Matthaeus, W. H.0000-0001-7224-6024
McNutt, R. L.0000-0002-4722-9166
Mewaldt, R. A.0000-0003-2178-9111
Mitchell, D. G.0000-0003-1960-2119
Pulupa, M.0000-0002-1573-7457
Rankin, J. S.0000-0002-8111-1444
Roelof, E. C.0000-0002-2270-0652
Stone, E. C.0000-0002-2010-5462
Szalay, J. R.0000-0003-2685-9801
Wiedenbeck, M. E.0000-0002-2825-3128
Additional Information:© ESO 2021. Article published by EDP Sciences. Received 7 September 2020; Accepted 14 November 2020. Published online 02 June 2021. We are deeply indebted to everyone that helped make the Parker Solar Probe (PSP) mission possible. We thank all of the outstanding scientists, engineers, technicians, and administrative support people across all of the IS⊙IS, FIELDS and SWEAP institutions that produced and supported the IS⊙IS, FIELDS and SWEAP instrument suites, support its operations and the scientific analysis of its data. This work was supported as part of the PSP mission under contract NNN06AA01C. NAS and CMSC were also supported under LWS grant “New Insights into SEP Sources, Acceleration, and Propagation: an Integrated Observation-Modeling Approach”, grant number 80NSSC19K0067. The IS⊙IS data and visualization tools are available to the community at:; data are also available via the NASA Space Physics Data Facility ( Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA’s Living with a Star (LWS) program (contract NNN06AA01C). Support from the LWS management and technical team has played a critical role in the success of the Parker Solar Probe mission.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:Sun: magnetic fields – solar wind – Sun: heliosphere – shock waves – acceleration of particles
Record Number:CaltechAUTHORS:20210609-073141024
Persistent URL:
Official Citation:A new view of energetic particles from stream interaction regions observed by Parker Solar Probe. N. A. Schwadron, C. J. Joyce, A. Aly, C. M. S. Cohen, M. I. Desai, D. J. McComas, J. T. Niehof, E. Möbius, M. Lee, J. Bower, S. Bale, A. Case, E. R. Christian, A. J. Davis, W. de Wet, K. Goetz, J. Giacalone, M. E. Hill, R. Allen, J. C. Kasper, K. Korreck, R. A. Leske, O. Malandraki, W. H. Matthaeus, R. L. McNutt, R. A. Mewaldt, D. G. Mitchell, M. Pulupa, J. S. Rankin, E. C. Roelof, E. C. Stone, J. R. Szalay and M. E. Wiedenbeck. A&A, 650 (2021) A24; DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109450
Deposited By: Tony Diaz
Deposited On:09 Jun 2021 18:02
Last Modified:09 Jun 2021 18:02

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