7–11 Jul 2025
University of the Witwatersrand, Johannesburg
Africa/Johannesburg timezone

Simulating cosmic ray diffusion coefficients in synthetic compressive magnetic turbulence

10 Jul 2025, 10:00
20m
Solomon Mahlangu House (University of the Witwatersrand, Johannesburg)

Solomon Mahlangu House

University of the Witwatersrand, Johannesburg

Oral Presentation Track D2 - Space Science Astrophysics & Space Science

Speaker

Jonathan Stephanus Troskie (North-West University; South African National Space Agency)

Description

In order to reliably estimate cosmic ray (CR) transport effects due to turbulence in the heliospheric magnetic field (HMF), and to validate existing diffusion theories (see, e.g., Engelbrecht et al., 2022, for a review), direct simulations, which involve solving the Newton-Lorentz equation numerically, may be employed (e.g., Els and Engelbrecht, 2024). Prior work, guided by turbulence conditions observed in the inner heliosphere, has largely focused on CR transport due to turbulence transverse to the background magnetic field. However, CR transport in the outer heliosphere, including in the heliosheath (HS), where HMF turbulence has been observed to have a compressive component (e.g., Fraternale et al., 2019), has, to date, received comparatively little attention. In this work, an approach to modelling HMF turbulence with an arbitrary compressive component, based on the synthetic turbulence model of Tautz and Dosch (2013), is suggested. Furthermore, turbulence parameters which may be expected in the HS are inferred from available analyses (e.g., Fraternale et al., 2019; Zhao et al., 2024). These parameters are then used as inputs for the particle pusher code detailed by Els and Engelbrecht (2024), modified so as to account for the presence of compressive turbulence, from which estimates for CR transport coefficients due to HMF turbulence conditions in the HS are calculated.

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Primary author

Jonathan Stephanus Troskie (North-West University; South African National Space Agency)

Co-author

Prof. Nicholas Eugene Engelbrecht (North-West University)

Presentation materials

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