München 2019 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 4: Sun and Heliosphere II

EP 4.2: Talk

Wednesday, March 20, 2019, 11:45–12:00, HS 19

Qualitative test particle simulations of pitch angle modifications due to Alfvénic waves — •Duncan Keilbach, Lars Berger, Verena Heidrich-Meisner, and Robert F. Wimmer-Schweingruber — Institut für Experimentelle und Angewandte Physik, Christian Albrechts Universität zu Kiel

We simulate the interaction of singly charged oxygen ions (treated as test particles) with Alfvénic cyclotron waves. In contrast to our preceding work, the pitch angle distribution of the test particles is not becoming isotropized when interacting with an intermittent mono-frequent wave field. Rather, the pitch angle distribution is governed by stationary patterns after an initial broadening. And that broadening has shown to be mainly a function of wave frequency and amplitude, as well as the phase difference between particle gyration and wave oscillation. A systematic study of these parameters may reveal insights about wave particle interactions on microscopic scales. E.g. resonances have shown to be less sharp than expected. Particles reacting strongest to the wave are found in a broad frequency area around first order resonance. The area's width is a function of the wave amplitude. Our approach is readily expandable to include a multitude of different modifications to the simulated magnetic field like the interaction with multiple wave frequencies or a change of the background magnetic field's strength and direction. It is also possible to include the interaction with multiple waves of e.g. varying frequencies and amplitudes.