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Title: Dynamics and density distributions in a capillary-discharge waveguide with an embedded supersonic jet

We present an analysis of the gas dynamics and density distributions within a capillary-discharge waveguide with an embedded supersonic jet. This device provides a target for a laser plasma accelerator which uses longitudinal structuring of the gas-density profile to enable control of electron trapping and acceleration. The functionality of the device depends sensitively on the details of the density profile, which are determined by the interaction between the pulsed gas in the jet and the continuously-flowing gas in the capillary. These dynamics are captured by spatially resolving recombination light from several emission lines of the plasma as a function of the delay between the jet and the discharge. We provide a phenomenological description of the gas dynamics as well as a quantitative evaluation of the density evolution. In particular, we show that the pressure difference between the jet and the capillary defines three regimes of operation with qualitatively different longitudinal density profiles and show that jet timing provides a sensitive method for tuning between these regimes.
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [1] ;  [3]
  1. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  2. Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22492977
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCELERATION; CAPILLARIES; DENSITY; EMISSION; LASER-PRODUCED PLASMA; PLASMA GUNS; PLASMA JETS; PULSES; RECOMBINATION; SPATIAL RESOLUTION; SUPERSONIC FLOW; TRAPPED ELECTRONS; VISIBLE RADIATION; WAVEGUIDES