A detailed survey of the parallel mean free path of solar energetic particle protons and electrons

Fuente: arXiv
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Main Authors: Lang, J. T., Strauss, R. D., Engelbrecht, N. E., Berg, J. P. van den, Dresing, N., Ruffolo, D., Bandyopadhyay, R.
Format: Preprint
Published: 2024
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author Lang, J. T.
Strauss, R. D.
Engelbrecht, N. E.
Berg, J. P. van den
Dresing, N.
Ruffolo, D.
Bandyopadhyay, R.
author_facet Lang, J. T.
Strauss, R. D.
Engelbrecht, N. E.
Berg, J. P. van den
Dresing, N.
Ruffolo, D.
Bandyopadhyay, R.
contents In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well-connected to at least one spacecraft at 1~au. The observed intensity-time profiles, for all available proton and electron energy channels, are compared to results computed using a numerical 1D SEP transport model in order to derive the parallel mean free paths (pMFPs) as a function of energy (or rigidity) at 1~au. These inversion results are then compared to theoretical estimates of the pMFP, using observed turbulence quantities with observationally-motivated variations as input. For protons, a very good comparison between inversion and theoretical results is obtained. It is shown that the observed inter-event variations in the inversion pMFP values can be explained by natural variations in the background turbulence values. For electrons, there is relatively good agreement with pMFPs derived assuming the damping model of dynamical turbulence, although the theoretical values are extremely sensitive to the details of the turbulence dissipation range which themselves display a high level of variation.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05765
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A detailed survey of the parallel mean free path of solar energetic particle protons and electrons
Lang, J. T.
Strauss, R. D.
Engelbrecht, N. E.
Berg, J. P. van den
Dresing, N.
Ruffolo, D.
Bandyopadhyay, R.
Solar and Stellar Astrophysics
Plasma Physics
Space Physics
In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well-connected to at least one spacecraft at 1~au. The observed intensity-time profiles, for all available proton and electron energy channels, are compared to results computed using a numerical 1D SEP transport model in order to derive the parallel mean free paths (pMFPs) as a function of energy (or rigidity) at 1~au. These inversion results are then compared to theoretical estimates of the pMFP, using observed turbulence quantities with observationally-motivated variations as input. For protons, a very good comparison between inversion and theoretical results is obtained. It is shown that the observed inter-event variations in the inversion pMFP values can be explained by natural variations in the background turbulence values. For electrons, there is relatively good agreement with pMFPs derived assuming the damping model of dynamical turbulence, although the theoretical values are extremely sensitive to the details of the turbulence dissipation range which themselves display a high level of variation.
title A detailed survey of the parallel mean free path of solar energetic particle protons and electrons
topic Solar and Stellar Astrophysics
Plasma Physics
Space Physics
url https://arxiv.org/abs/2406.05765