Self-injection by trapping of plasma electrons oscillating in rising density gradient at the vacuum-plasma interface

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Title: Self-injection by trapping of plasma electrons oscillating in rising density gradient at the vacuum-plasma interface
Authors: Sahai, AA
Katsouleas, TC
Muggli, P
Item Type: Conference Paper
Abstract: We model the trapping of plasma $e^-$ within the density structures excited by a propagating energy source ($beta_{S}simeq1$) in a rising plasma density gradient. Rising density gradient leads to spatially contiguous coupled up-chirped plasmons ($d{omega^2_{pe}(x)}/{dx}>0$). Therefore phase mixing between plasmons can lead to trapping until the plasmon field is high enough such that $e^-$ trajectories returning towards a longer wavelength see a trapping potential. Rising plasma density gradients are ubiquitous for confining the plasma within sources at the vacuum-plasma interfaces. Therefore trapping of plasma-$e^-$ in a rising ramp is important for acceleration diagnostics and to understand the energy dissipation from the excited plasmon train cite{LTE-2013}. Down-ramp in density cite{density-transition-2001} has been used for plasma-$e^-$ trapping within the first bucket behind the driver. Here, in rising density gradient the trapping does not occur in the first plasmon bucket but in subsequent plasmon buckets behind the driver. Trapping reduces the Hamiltonian of each bucket where $e^-$ are trapped, so it is a wakefield-decay probe. Preliminary computational results for beam and laser-driven wakefield are shown.
Issue Date: 31-Jul-2014
Date of Acceptance: 14-Jun-2014
ISBN: 978-3-95450-132-8
Publisher: JACoW
Start Page: 1479
End Page: 1482
Journal / Book Title: Proceedings of IPAC 2014
Copyright Statement: © 2014 CC-BY-3.0 and by the respective authors
Conference Name: IPAC 2014
Keywords: physics.plasm-ph
Plasma physics
Accelerator physics
Computational physics
Notes: Proceedings of International Particle Accelerator Conference, IPAC 2014, Dresden, Germany, June 2014,
Start Date: 2014-06-15
Finish Date: 2014-06-20
Conference Place: Dresden, Germany
Appears in Collections:Physics
Plasma Physics
Faculty of Natural Sciences

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