Selfsimilar expansion of finitesize nonquasineutral plasmas into vacuum: Relation to the problem of ion acceleration
Abstract
A new selfsimilar solution is presented which describes nonrelativistic expansion of a finite plasma mass into vacuum with a full account of charge separation effects. The solution exists only when the ratio {lambda}=R/{lambda}{sub D} of the plasma scale length R to the Debye length {lambda}{sub D} is invariant, i.e., under the condition T{sub e}(t){proportional_to}[n{sub e}(t)]{sup 12{nu}}, where {nu}=1, 2, and 3 corresponds, respectively, to the planar, cylindrical, and spherical geometries. For {lambda}>>1 the position of the ion front and the maximum energy E{sub i,max} of accelerated ions are calculated analytically: in particular, for {nu}=3 one finds E{sub i,max}=2ZT{sub e0}W({lambda}{sup 2}/2), where T{sub e0} is the initial electron temperature, Z is the ion charge, and W is the Lambert W function. It is argued that, when properly formulated, the results for E{sub i,max} can be applied more generally than the selfsimilar solution itself. Generalization to a twotemperature electron system reveals the conditions under which the highenergy tail of accelerated ions is determined solely by the hotelectron population.
 Authors:
 Institute of Laser Engineering, Osaka University, Yamadaoka 26, Suita, Osaka 5650871 (Japan)
 Publication Date:
 OSTI Identifier:
 20782425
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 1; Other Information: DOI: 10.1063/1.2162527; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; CYLINDRICAL CONFIGURATION; DEBYE LENGTH; ELECTRON TEMPERATURE; ELECTRONS; FRACTALS; GEOMETRY; ION TEMPERATURE; IONS; MATHEMATICAL SOLUTIONS; PLASMA; PLASMA EXPANSION; PLASMA GUNS
Citation Formats
Murakami, M., and Basko, M.M. Selfsimilar expansion of finitesize nonquasineutral plasmas into vacuum: Relation to the problem of ion acceleration. United States: N. p., 2006.
Web. doi:10.1063/1.2162527.
Murakami, M., & Basko, M.M. Selfsimilar expansion of finitesize nonquasineutral plasmas into vacuum: Relation to the problem of ion acceleration. United States. doi:10.1063/1.2162527.
Murakami, M., and Basko, M.M. Sun .
"Selfsimilar expansion of finitesize nonquasineutral plasmas into vacuum: Relation to the problem of ion acceleration". United States.
doi:10.1063/1.2162527.
@article{osti_20782425,
title = {Selfsimilar expansion of finitesize nonquasineutral plasmas into vacuum: Relation to the problem of ion acceleration},
author = {Murakami, M. and Basko, M.M.},
abstractNote = {A new selfsimilar solution is presented which describes nonrelativistic expansion of a finite plasma mass into vacuum with a full account of charge separation effects. The solution exists only when the ratio {lambda}=R/{lambda}{sub D} of the plasma scale length R to the Debye length {lambda}{sub D} is invariant, i.e., under the condition T{sub e}(t){proportional_to}[n{sub e}(t)]{sup 12{nu}}, where {nu}=1, 2, and 3 corresponds, respectively, to the planar, cylindrical, and spherical geometries. For {lambda}>>1 the position of the ion front and the maximum energy E{sub i,max} of accelerated ions are calculated analytically: in particular, for {nu}=3 one finds E{sub i,max}=2ZT{sub e0}W({lambda}{sup 2}/2), where T{sub e0} is the initial electron temperature, Z is the ion charge, and W is the Lambert W function. It is argued that, when properly formulated, the results for E{sub i,max} can be applied more generally than the selfsimilar solution itself. Generalization to a twotemperature electron system reveals the conditions under which the highenergy tail of accelerated ions is determined solely by the hotelectron population.},
doi = {10.1063/1.2162527},
journal = {Physics of Plasmas},
number = 1,
volume = 13,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}

Ion acceleration is studied both analytically and numerically. In the analytical model, a new selfsimilar solution, which can be applied to any geometry (planar, cylindrical, and spherical), is employed to describe nonrelativistic expansion of a finite plasma mass into vacuum with a full account of charge separation effects. It turns out that the normalized plasma size {lambda} = R/{lambda}D plays the dominant role in determining the whole ion energy spectrum and thus the maximum ion kinetic energy, where R and {lambda}D are the plasma scale length and the Debye length, respectively. The analytical model is compared with particle simulations andmore »

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