Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles
Issued Date
2024-06-01
Resource Type
ISSN
0004637X
eISSN
15384357
Scopus ID
2-s2.0-85194098089
Journal Title
Astrophysical Journal
Volume
967
Issue
2
Rights Holder(s)
SCOPUS
Bibliographic Citation
Astrophysical Journal Vol.967 No.2 (2024)
Suggested Citation
Sonsrettee W., Chuychai P., Seripienlert A., Tooprakai P., Sáiz A., Ruffolo D., Matthaeus W.H., Chhiber R. Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles. Astrophysical Journal Vol.967 No.2 (2024). doi:10.3847/1538-4357/ad3d58 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/98559
Title
Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles
Corresponding Author(s)
Other Contributor(s)
Abstract
Modeling of time profiles of solar energetic particle (SEP) observations often considers transport along a large-scale magnetic field with a fixed path length from the source to the observer. Here, we point out that variability in the turbulent field line path length can affect the fits to SEP data and the inferred mean free path and injection profile. To explore such variability, we perform Monte Carlo simulations in representations of homogeneous 2D MHD + slab turbulence adapted to spherical geometry and trace trajectories of field lines and full particle orbits, considering proton injection from a narrow or wide angular region near the Sun, corresponding to an impulsive or gradual solar event, respectively. We analyze our simulation results in terms of field line and particle path length statistics for 1° × 1° pixels in heliolatitude and heliolongitude at 0.35 and 1 au from the Sun, for different values of the turbulence amplitude b/B 0 and turbulence geometry as expressed by the slab fraction f s . Maps of the most probable path lengths of field lines and particles at each pixel exhibit systematic patterns that reflect the fluctuation amplitudes experienced by the field lines, which in turn relate to the local topology of 2D turbulence. We describe the effects of such path length variations on SEP time profiles, both in terms of path length variability at specific locations and the motion of the observer with respect to turbulence topology during the course of the observations.