Quantification of particle scattering and transport by solar wind current sheets

poster

Introduction & Motivation

The transport of energetic particles within the heliosphere is significantly influenced by the turbulent magnetic field present in the solar wind Pucci et al. (2016). Rather than being a simple superposition of random fluctuations, these turbulent fields exhibit a structured nature, frequently observed in the solar wind magnetic field in the form of current sheets, discontinuities, Alfvén vortices, magnetic holes, and other coherent structures D. Perrone et al. (2016). These structures arise from nonlinear energy cascade processes Meneguzzi, Frisch, and Pouquet (1981) and play a critical role in modulating particle transport.

Method

We developed an analytical Hamiltonian framework that incorporates the effect of magnetic field rotation.

We compiled a dataset of 100,000 current sheets charaterizing the current sheet parameters (\(\theta\), \(\beta\), \(\log \tilde{v}_B\)) from the ARTEMIS and Wind missions.

We conducted extensive test particle simulations to quantitatively model particle scattering and transport due to interactions with current sheets.

Transition matrix for 100 keV protons under four distinct magnetic field configurations:

We modelled the long-term pitch-angle evolution of particles in the presence of current sheets using mapping techniques.

Second moment of the pitch-angle distribution, \(M_2(n)\), as a function of interaction number (\(n\)) for different particle energies

Pitch-angle diffusion rates \(\mathcal{D}_{μμ}\) as a function of particle energy \(E\).

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Perrone, Denise, Roberto Bruno, Raffaella D’Amicis, Daniele Telloni, Rossana De Marco, Marco Stangalini, Silvia Perri, Oreste Pezzi, Olga Alexandrova, and Stuart D. Bale. 2020. “Coherent Events at Ion Scales in the Inner Heliosphere: Parker Solar Probe Observations During the First Encounter.” Astrophysical Journal 905 (2): 142. https://doi.org/10.3847/1538-4357/abc480.

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