SMuK 2023 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 9: Poster
EP 9.8: Poster
Wednesday, March 22, 2023, 17:30–19:00, HSZ OG1
Evolution and radio emission of interacting plasma bunches in pulsar magnetospheres — •Jan Benáček1, Patricio Muñoz2,3, Jörg Büchner3,2, and Axel Jessner4 — 1Intitute for Physics and Astronomy, University of Potsdam, Germany — 2Max Planck Institute for Solar System Physics, Göttingen, Germany — 3Center for Astronomy and Astrophysics, Technical University of Berlin, Germany — 4Max Planck Institute for Radio Astronomy, Bonn, Germany
Pulsars are neutron star that emits coherent radio beams out of their magnetic poles. However, the origin of their radio emission is still under investigation. One of the proposed emission mechanisms exploits plasma bunches/clouds of electron-positron pairs created during spark events in gap regions. We utilized particle-in-cell simulations of relativistically hot bunches to investigate the bunch's nonlinear evolution and radiation by linear acceleration emission. We found that the main parameter influencing the bunch evolution is the initial drift velocity between electrons and positrons. For zero drift, the bunches can freely expand, and adjacent bunches may overlap in the phase space and form relativistic streaming instability. Otherwise, for non-zero drifts, the bunches are constrained from expansion and form strong oscillating electrostatic fields. Plasma particles may oscillate in these fields and emit radio waves. Furthermore, we found that the bunches constrained from expansion have similar observational characteristics as those observed for pulsars. Their spectrum contains a flat part for low frequencies and power-law profiles for higher frequencies.