Greifswald 2024 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 7: Sun and Heliosphere II

EP 7.10: Talk

Thursday, February 29, 2024, 16:45–17:00, ELP 6: HS 2

Solar energetic particle transport, gamma ray flares and intermittent turbulence — •Frederic Effenberger, Jeremiah Lübke, Julien Dörner, Horst Fichtner, and Rainer Grauer — Theoretische Physik, Ruhr-Universität Bochum, Germany

The detailed understanding and ultimately the ability to forecast solar energetic particle (SEP) events is critical in our efforts to mitigate space weather risks. I will discuss current issues in SEP modelling and observations with a particular focus on non-thermal particle sources in solar flares and CME shocks, and cross-field transport effects due to solar wind structures and field line random walk. Of particular interest are coherent features in the solar wind turbulence that can influence particle transport behaviour. Synthetic fields to study particle transport are typically generated from superpositions of Fourier modes with a prescribed power spectrum and uncorrelated random phases, bringing the advantage of covering a wide range of turbulence scales at manageable computational effort. However, almost all of these models to date only account for second-order Gaussian statistics and thus fail to include intermittent features. We have developed a novel method to account for this shortcoming based on a minimal Lagrangian map approach. We investigate the particle transport properties by solving a large number of particle orbits in these synthetic turbulence realisations and specifically look for non-diffusive regimes and non-standard energy dependences resulting from the intermittency of the generated fields. Applications to SEP transport and the production of gamma rays from solar events will be discussed.

Keywords: Solar Energetic Particles; Turbulence; Gamma Rays; Coronal Mass Ejections; Magnetohydrodynamics