Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

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    We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥ 1 T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background  electron-ion plasma. The experimentally determined equipartition parameter of ϵB ≈ 10−3 is typical of
    values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.



    Original languageEnglish
    Article number185002
    Number of pages5
    JournalPhysical Review Letters
    Journal publication date03 Nov 2017
    Publication statusPublished - 03 Nov 2017

    ID: 136133836