Greifswald 2024 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 7: Sun and Heliosphere II

EP 7.11: Talk

Thursday, February 29, 2024, 17:00–17:15, ELP 6: HS 2

Structured Synthetic Turbulence and Solar Energetic Particle Transport — •Jeremiah Lübke¹, Frederic Effenberger², Mike Wilbert¹, Horst Fichtner², and Rainer Grauer¹ — ¹Institute for Theoretical Physics I, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum — ²Institute for Theoretical Physics IV, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum

Turbulence is ubiquitous in the solar wind, however its impact on the transport of solar energetic particles is poorly understood, since global simulations of the heliosphere are not able to resolve the turbulent length scales properly. This issue can be mitigated by employing synthetic turbulence, which is usually modelled as scale-invariant ``smart noise'' via sums of waves with a prescribed power spectrum and random uncorrelated phases. We present a novel model for synthetic turbulence, which is more faithful to the complex intermittent character of realistic turbulence, which is dominated by low-curvature coherent structures and high-curvature intense scattering sites. The model is a combination of a log-normal cascade and the multiscale minimal Lagrangian mapping approach. We investigate the resulting vector fields with regard to structure function scaling, fieldline geometry and energetic particle transport properties. Magnetohydrodynamic simulations of turbulence are consulted for comparison. We find that energetic particle diffusion is significantly enhanced by a combination of extended coherent structures and intense high-curvature scattering sites. Finally, applications to specific phenomena in the heliosphere, such as CME sheath turbulence, are discussed.

Keywords: Magnetic Turbulence; Intermittency; Coherent structures; Energetic particle transport; Pitch-angle scattering