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Title: Three-dimensional imaging of the ultracold plasma formed in a supersonic molecular beam

Double-resonant excitation of nitric oxide in a seeded supersonic molecular beam forms a state-selected Rydberg gas that evolves to form an ultracold plasma. This plasma travels with the propagation of the molecular beam in z over a variable distance as great as 600 mm to strike an imaging detector, which records the charge distribution in the dimensions, x and y. The ω{sub 1} + ω{sub 2} laser crossed molecular beam excitation geometry convolutes the axial Gaussian distribution of NO in the molecular beam with the Gaussian intensity distribution of the perpendicularly aligned laser beam to create an ellipsoidal volume of Rydberg gas. Detected images describe the evolution of this initial density as a function of selected Rydberg gas initial principal quantum number, n{sub 0}, ω{sub 1} laser pulse energy (linearly related to Rydberg gas density, ρ{sub 0}) and flight time. Low-density Rydberg gases of lower principal quantum number produce uniformly expanding, ellipsoidal charge-density distributions. Increase either of n{sub 0} or ρ{sub 0} breaks the ellipsoidal symmetry of plasma expansion. The volume bifurcates to form repelling plasma volumes. The velocity of separation depends on n{sub 0} and ρ{sub 0} in a way that scales uniformly with ρ{sub e}, the density of electronsmore » formed in the core of the Rydberg gas by prompt Penning ionization. Conditions under which this electron gas drives expansion in the long axis dimension of the ellipsoid favours the formation of counter-propagating shock waves.« less
Authors:
;  [1]
  1. Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1 Canada (Canada)
Publication Date:
OSTI Identifier:
22490701
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1668; Journal Issue: 1; Conference: 11. international workshop on non-neutral plasmas, Takamatsu (Japan), 1-4 Dec 2014; 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; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CHARGE DENSITY; CHARGE DISTRIBUTION; DENSITY; ELECTRON GAS; ELECTRONS; EXCITATION; GASES; GAUSS FUNCTION; IONIZATION; LASERS; MOLECULAR BEAMS; NITRIC OXIDE; PLASMA; PLASMA EXPANSION; SHOCK WAVES; THREE-DIMENSIONAL CALCULATIONS; THREE-DIMENSIONAL LATTICES; VELOCITY