PSP Bibliography


  • Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher.
  • Clicking on a single author will show all publications by the selected author.
  • Clicking on a single keyword, will show all publications by the selected keyword.

Time evolution of stream interaction region energetic particle spectra in the inner heliosphere

AuthorJoyce, C.; McComas, D.; Schwadron, N.; Christian, E.; Wiedenbeck, M.; McNutt, R.; Cohen, C.; Leske, R.; Mewaldt, R.; Stone, E.; Labrador, A.; Davis, A.; Cummings, A.; Mitchell, D.; Hill, M.; Roelof, E.; Allen, R.; Szalay, J.; Rankin, J.; Desai, M.; Giacalone, J.; Matthaeus, W.; Bale, S.; Kasper, J.;
Keywordsacceleration of particles; Solar wind; magnetic fields; Parker Data Used
AbstractWe analyze an energetic proton event associated with a stream interaction region (SIR) that was observed at Parker Solar Probe on day 320 of 2018 when the spacecraft was just 0.34 AU from the Sun. Using the Integrated Science Investigation of the Sun instrument suite, we perform a spectral analysis of the event and show how the observed spectra evolve over the course of the event. We find that the spectra from the first day of the event are much more consistent with local acceleration at a weak compression, while spectra from later on are more typical of SIR-related events in which particles accelerated at distant shocks dominate. After the first day, the spectra remain approximately constant, which indicates that the modulation of energetic particles during transit from the presumed source region is weaker than previously thought. We argue that these observations can be explained by a sub-Parker spiral magnetic field structure connecting the spacecraft to a source region in the SIR that is relatively close to the Sun. We further propose that acceleration at weak, pre-shock compressions likely plays an important role in observations of SIR-related events in the inner heliosphere and that future modelling of such events should consider acceleration all along the compression region, not just at the distant shock region.
Year of Publication2021
JournalAstronomy and Astrophysics
Number of PagesL5
Date Published06/2021