%0 Journal Article %1 Burkart_2010 %A Burkart, T. %A Elbracht, O. %A Ganse, U. %A Spanier, F. %D 2010 %J \apj %K acceleration galaxies: instabilities, jets, methods: numerical, of particles, plasmas %N 2 %P 1318-1324 %R 10.1088/0004-637X/720/2/1318 %T The Influence of the Mass Ratio on the Acceleration of Particles by Filamentation Instabilities %U http://stacks.iop.org/0004-637X/720/i=2/a=1318 %V 720 %X Almost all sources of high-energy particles and photons are associated with jet phenomena. Prominent sources of such highly relativistic outflows are pulsar winds, active galactic nuclei (AGNs), and gamma-ray bursts. The current understanding of these jets assumes diluted plasmas which are best described as kinetic phenomena. In this kinetic description, particle acceleration to ultrarelativistic speeds can occur in completely unmagnetized and neutral plasmas through insetting effects of instabilities. Even though the morphology and nature of particle spectra are understood to a certain extent, the composition of the jets is not known yet. While Poynting-flux-dominated jets (e.g., occurring in pulsar winds) are certainly composed of electron-positron plasmas, the understanding of the governing physics in AGN jets is mostly unclear. In this paper, we investigate how the constituting elements of an electron-positron-proton plasma behave differently under the variation of the fundamental mass ratio m p / m e . We initially studied unmagnetized counterstreaming plasmas using fully relativistic three-dimensional particle-in-cell simulations to investigate the influence of the mass ratio on particle acceleration and magnetic field generation in electron-positron-proton plasmas. We covered a range of mass ratios m p / m e between 1 and 100 with a particle number composition of ##IMG## http://ej.iop.org/images/0004-637X/720/2/1318/apj328795ieqn1.gif $n_p^+ / n_e^+$ of 1 in one stream, therefore called the pair-proton stream. Protons are injected in the other one, therefore from now on called the proton stream, whereas electrons are present in both to guarantee charge neutrality in the simulation box. We find that with increasing proton mass the instability takes longer to develop and for mass ratios >20 the particles seem to be accelerated in two phases which can be accounted for by the individual instabilities of the different species. This means that for high mass ratios the coupling between electrons/positrons and the heavier protons, which occurs in low mass ratios, disappears.

@article{Burkart_2010, abstract = {Almost all sources of high-energy particles and photons are associated with jet phenomena. Prominent sources of such highly relativistic outflows are pulsar winds, active galactic nuclei (AGNs), and gamma-ray bursts. The current understanding of these jets assumes diluted plasmas which are best described as kinetic phenomena. In this kinetic description, particle acceleration to ultrarelativistic speeds can occur in completely unmagnetized and neutral plasmas through insetting effects of instabilities. Even though the morphology and nature of particle spectra are understood to a certain extent, the composition of the jets is not known yet. While Poynting-flux-dominated jets (e.g., occurring in pulsar winds) are certainly composed of electron-positron plasmas, the understanding of the governing physics in AGN jets is mostly unclear. In this paper, we investigate how the constituting elements of an electron-positron-proton plasma behave differently under the variation of the fundamental mass ratio m p / m e . We initially studied unmagnetized counterstreaming plasmas using fully relativistic three-dimensional particle-in-cell simulations to investigate the influence of the mass ratio on particle acceleration and magnetic field generation in electron-positron-proton plasmas. We covered a range of mass ratios m p / m e between 1 and 100 with a particle number composition of ##IMG## [http://ej.iop.org/images/0004-637X/720/2/1318/apj328795ieqn1.gif] {$n_{p^+} / n_{e^+}$} of 1 in one stream, therefore called the pair-proton stream. Protons are injected in the other one, therefore from now on called the proton stream, whereas electrons are present in both to guarantee charge neutrality in the simulation box. We find that with increasing proton mass the instability takes longer to develop and for mass ratios >20 the particles seem to be accelerated in two phases which can be accounted for by the individual instabilities of the different species. This means that for high mass ratios the coupling between electrons/positrons and the heavier protons, which occurs in low mass ratios, disappears.}, added-at = {2012-04-11T14:04:10.000+0200}, adsurl = {http://esoads.eso.org/abs/2010ApJ...720.1318B}, author = {{Burkart}, T. and {Elbracht}, O. and {Ganse}, U. and {Spanier}, F.}, biburl = {https://www.bibsonomy.org/bibtex/232e1bdba0b8751bcf4fed85bfa22c4f7/pkilian}, doi = {10.1088/0004-637X/720/2/1318}, eprint = {1007.1876}, interhash = {1b9e88a29a15b08d539a4ee30d14600a}, intrahash = {32e1bdba0b8751bcf4fed85bfa22c4f7}, journal = {\apj}, keywords = {acceleration galaxies: instabilities, jets, methods: numerical, of particles, plasmas}, month = sep, number = 2, pages = {1318-1324}, timestamp = {2012-04-11T14:04:11.000+0200}, title = {{The Influence of the Mass Ratio on the Acceleration of Particles by Filamentation Instabilities}}, url = {http://stacks.iop.org/0004-637X/720/i=2/a=1318}, volume = 720, year = 2010 }