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

Warwick, J. and Dzelzainis, T. and Dieckmann, M. E. and Schumaker, W. and Doria, D. and Romagnani, L. and Poder, K. and Cole, J. M. and Alejo, A. and Yeung, M. and Krushelnick, K. and Mangles, S. P. D. and Najmudin, Z. and Reville, B. and Samarin, G. M. and Symes, D. D. and Thomas, A. G. R. and Borghesi, M. and Sarri, G. (2017) Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam. Physical review letters, 119 (18). ISSN 0031-9007

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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 epsilon(B) approximate to 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.

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Journal Article
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Physical review letters
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©2017 American Physical Society.
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Deposited On:
04 Dec 2017 12:02
Last Modified:
22 Nov 2022 05:14