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Title: Transport properties of a hollow pressure filament in a magnetized plasma

Publication Date:
Sponsoring Org.:
OSTI Identifier:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 9; Related Information: CHORUS Timestamp: 2016-12-26 00:45:12; Journal ID: ISSN 1070-664X
American Institute of Physics
Country of Publication:
United States

Citation Formats

Poulos, M. J., and Morales, G. J.. Transport properties of a hollow pressure filament in a magnetized plasma. United States: N. p., 2016. Web. doi:10.1063/1.4962574.
Poulos, M. J., & Morales, G. J.. Transport properties of a hollow pressure filament in a magnetized plasma. United States. doi:10.1063/1.4962574.
Poulos, M. J., and Morales, G. J.. 2016. "Transport properties of a hollow pressure filament in a magnetized plasma". United States. doi:10.1063/1.4962574.
title = {Transport properties of a hollow pressure filament in a magnetized plasma},
author = {Poulos, M. J. and Morales, G. J.},
abstractNote = {},
doi = {10.1063/1.4962574},
journal = {Physics of Plasmas},
number = 9,
volume = 23,
place = {United States},
year = 2016,
month = 9

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4962574

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  • Diffusion of a low-pressure (10/sup -2/ Torr) hollow-cathode discharge through an anode screen produces a linear, homogeneous, and quiescent plasma column (14 mm in diameter, 80 cm in length) in a strong magnetic field (max 3 kG). Electron temperatures and densities in this plasma, as measured by Langmuir probe and microwave cavity perturbation techniques are, respectively, in the ranges of 0.3--1.2 eV and 10/sup 9/--10/sup 11/ cm/sup -3/. Plasma noise fluctuations (eapprox. =/sub fl//k/sub B/T/sub e/) at the center of the plasma are about 3%.
  • A complete description of a system in equilibrium is provided by the Grand Canonical Distribution. But, systems are generally not in statistical equilibrium. We shall consider the case of an ideal gaz of charged particles. The linear theory of transport determines the 3 x 1 matrix of dissipative fluxes [circumflex]J{sub r} namely, the electric current and the electronic and ionic heat fluxes, in terms of a 3 x 1 matrix of thermodynamic forces [circumflex]X defined by the electric field and the gradient of the densities and temperatures. The components of the 3 x 3 matrix of tensors [circumflex]L{sub rs} ofmore » the linear flux-force relations [circumflex]J{sub r} [summation]{sub s=1}{sup 9}[circumflex]L{sub rs}[circumflex]X define the set of transport coefficients. They are evaluated for an ion-electron magnetized plasma in the framework of the statistical mechanics of charged particles starting from the Landau kinetic equation.« less
  • We have explored here a hollow cylindrical laser plasma multifilament waveguide with discontinuous finite thickness cladding, in which the separation between individual filaments is in the range of several millimeters and the waveguide cladding thickness is in the order of the microwave penetration depth. Such parameters give a closer representation of a realistic laser filament waveguide sustained by a long stable propagation of femtosecond (fs) laser pulses. We report how the waveguide losses depend on structural parameters like normalized plasma filament spacing, filament to filament distance or pitch, normal spatial frequency, and radius of the plasma filament. We found thatmore » for typical plasma parameters, the proposed waveguide can support guided modes of microwaves in extremely high frequency even with a cladding consisting of only one ring of plasma filaments. The loss of the microwave radiation is mainly caused by tunneling through the discontinuous finite cladding, i.e., confinement loss, and is weakly dependent on the plasma absorption. In addition, the analysis indicates that the propagation loss is fairly large compared with the loss of a plasma waveguide with a continuous infinite thickness cladding, while they are comparable when using a cladding contains more than one ring. Compared to free space propagation, this waveguide still presents a superior microwave transmission to some distance in the order of the filamentation length; thus, the laser plasma filaments waveguide may be a potential channel for transporting pulsed-modulated microwaves if ensuring a long and stable propagation of fs laser pulses.« less
  • This experiment illustrates the spatiotemporal pattern of the fluctuations that spontaneously develop in a magnetized temperature filament whose transverse scale is comparable to the electron skin depth. A high-frequency mode exhibits a striking spiral structure and is identified as a drift-Alfven eigenmode. A low-frequency mode is found to be localized near the center of the filament. It is documented that the fluctuations significantly increase the transport of heat beyond the prediction of classical theory based on Coulomb collisions. (c) 2000 The American Physical Society.
  • A systematic study is made of the spontaneous growth of fluctuations in temperature, density, and magnetic field in a narrow (on the order of the electron skin depth) field-aligned temperature filament embedded in a large magnetized plasma. Two broad classes of fluctuation (''low'' and ''high'' frequency modes) have been identified and studied in detail. A high-frequency drift-Alfven mode grows at frequencies about one tenth the ion gyrofrequency in the region of the filament where the temperature gradient is large. The measured radial profiles of the density and magnetic field fluctuations associated with this mode agree well with theoretical predictions. Themore » high-frequency mode has been observed to exhibit several interesting nonlinear features, including steepening wave form, progression in azimuthal mode number, coupling to the low frequency mode with subsequent sideband generation, and eventually a transition to broad band turbulence. The nature of the low-frequency mode which has frequencies about one fiftieth of the ion gyrofrequency is less certain, but it has been identified as a spatially localized, azimuthally symmetric mode consisting primarily of temperature fluctuations. Both the high and low-frequency modes give rise to electron heat transport at rates in excess of the classical values. (c) 2000 American Institute of Physics.« less