Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles

Fuente: arXiv
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Main Authors: Sonsrettee, Wirin, Chuychai, Piyanate, Seripienlert, Achara, Tooprakai, Paisan, Sáiz, Alejandro, Ruffolo, David, Matthaeus, William H., Chhiber, Rohit
Format: Preprint
Published: 2024
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author Sonsrettee, Wirin
Chuychai, Piyanate
Seripienlert, Achara
Tooprakai, Paisan
Sáiz, Alejandro
Ruffolo, David
Matthaeus, William H.
Chhiber, Rohit
author_facet Sonsrettee, Wirin
Chuychai, Piyanate
Seripienlert, Achara
Tooprakai, Paisan
Sáiz, Alejandro
Ruffolo, David
Matthaeus, William H.
Chhiber, Rohit
contents 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 $1^\circ\times 1^\circ$ 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 motion of the observer with respect to turbulence topology during the course of the observations.
format Preprint
id arxiv_https___arxiv_org_abs_2404_14718
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles
Sonsrettee, Wirin
Chuychai, Piyanate
Seripienlert, Achara
Tooprakai, Paisan
Sáiz, Alejandro
Ruffolo, David
Matthaeus, William H.
Chhiber, Rohit
Solar and Stellar Astrophysics
Space Physics
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 $1^\circ\times 1^\circ$ 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 motion of the observer with respect to turbulence topology during the course of the observations.
title Variation in Path Lengths of Turbulent Magnetic Field Lines and Solar Energetic Particles
topic Solar and Stellar Astrophysics
Space Physics
url https://arxiv.org/abs/2404.14718