Two-dimensional PIC simulations of ion beam instabilities in Supernova-driven plasma flows
2008 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 50, 065020-1-14 p.Article in journal (Refereed) Published
Supernova remnant blast shells can reach the flow speed vs = 0.1c and shocks form at its front. Instabilities driven by shock-reflected ion beams heat the plasma in the foreshock, which may inject particles into diffusive acceleration. The ion beams can have the speed vb vs. For vb vs the Buneman or upper-hybrid instabilities dominate, while for vb vs the filamentation and mixed modes grow faster. Here the relevant waves for vb vs are examined and how they interact nonlinearly with the particles. The collision of two plasma clouds at the speed vs is modelled with particle-in-cell simulations, which convect with them magnetic fields oriented perpendicular to their flow velocity vector. One simulation models equally dense clouds and the other one uses a density ratio of 2. Both simulations show upper-hybrid waves that are planar over large spatial intervals and that accelerate electrons to ~10 keV. The symmetric collision yields only short oscillatory wave pulses, while the asymmetric collision also produces large-scale electric fields, probably through a magnetic pressure gradient. The large-scale fields destroy the electron phase space holes and they accelerate the ions, which facilitates the formation of a precursor shock.
Place, publisher, year, edition, pages
2008. Vol. 50, 065020-1-14 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-42495DOI: 10.1088/0741-3335/50/6/065020Local ID: 65119OAI: oai:DiVA.org:liu-42495DiVA: diva2:263352