skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Instability of the Electron Gas in an Expanding Metal

Abstract

We have measured x-ray diffraction and small-angle x-ray scattering of fluid rubidium by reducing electron density down to the range where the compressibility of the interacting electron gas has been theoretically predicted to become negative. Negative compressibility is closely associated with a negative value of the static dielectric function, which makes the screened Coulomb interaction among like charges overall attractive. It was clearly observed that the interatomic distance decreases in spite of the fact that mean interatomic distance increases with expansion, suggesting that an attractive interaction among like charges, ions in this case, is enhanced. These findings indicate that the observed structural features are evidence of the compressional instability of the 3D electron gas.

Authors:
;  [1];  [2]
  1. Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan)
  2. Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi Hiroshima 739-8521 (Japan)
Publication Date:
OSTI Identifier:
20957709
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevLett.98.096401; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPRESSIBILITY; DIELECTRIC MATERIALS; ELECTRON DENSITY; ELECTRON GAS; EXPANSION; INSTABILITY; INTERATOMIC DISTANCES; RUBIDIUM; SMALL ANGLE SCATTERING; X-RAY DIFFRACTION

Citation Formats

Matsuda, K., Tamura, K., and Inui, M.. Instability of the Electron Gas in an Expanding Metal. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.096401.
Matsuda, K., Tamura, K., & Inui, M.. Instability of the Electron Gas in an Expanding Metal. United States. doi:10.1103/PHYSREVLETT.98.096401.
Matsuda, K., Tamura, K., and Inui, M.. Fri . "Instability of the Electron Gas in an Expanding Metal". United States. doi:10.1103/PHYSREVLETT.98.096401.
@article{osti_20957709,
title = {Instability of the Electron Gas in an Expanding Metal},
author = {Matsuda, K. and Tamura, K. and Inui, M.},
abstractNote = {We have measured x-ray diffraction and small-angle x-ray scattering of fluid rubidium by reducing electron density down to the range where the compressibility of the interacting electron gas has been theoretically predicted to become negative. Negative compressibility is closely associated with a negative value of the static dielectric function, which makes the screened Coulomb interaction among like charges overall attractive. It was clearly observed that the interatomic distance decreases in spite of the fact that mean interatomic distance increases with expansion, suggesting that an attractive interaction among like charges, ions in this case, is enhanced. These findings indicate that the observed structural features are evidence of the compressional instability of the 3D electron gas.},
doi = {10.1103/PHYSREVLETT.98.096401},
journal = {Physical Review Letters},
number = 9,
volume = 98,
place = {United States},
year = {Fri Mar 02 00:00:00 EST 2007},
month = {Fri Mar 02 00:00:00 EST 2007}
}
  • A self-focused electron beam produces a string of hot spots along its path in 0.35 Torr of air. In this communication we report some interesting snap shots on the luminous gas bubbles expanding from the pinched hot spots. The radial speed of expansion is measured to be approx.9 mm/..mu..sec, which corresponds to approx.6 eV of kinetic energy per N/sup +/ ion.
  • This paper investigates theoretically the electrostatic stability properties of a nonneutral electron plasma interacting with background neutral gas through elastic collisions with constant collision frequency {nu}{sub {ital en}}. The model treats the electrons as a strongly magnetized fluid ({omega}{sub {ital pe}}{sup 2}/{omega}{sub {ital ce}}{sup 2}{lt}1) immersed in a uniform magnetic field {ital B}{sub 0}{bold {cflx e}}{sub {bold z}}, and assumes small-amplitude perturbations with azimuthal mode number l=1 and negligible axial variation ({partial_derivative}/{partial_derivative}{ital z}=0). The analysis also assumes weak electron collisions with {nu}{sub {ital en}}/{omega}{sub {ital ce}}={epsilon}{lt}1, and that the process of heat conduction is sufficiently fast that the electrons havemore » relaxed through electron-electron collisions to a quasiequilibrium state with scalar pressure {ital P}({ital r},{theta},{ital t})={ital n}({ital r},{theta},{ital t}){ital T}, and isothermal temperature {ital T}. Assuming that perturbed quantities vary with time according to exp({minus}{ital i}{omega}{ital t}), the detailed stability analysis carried out to first order in {nu}{sub {ital en}}/{omega}{sub {ital ce}}{lt}1 shows that the real oscillation frequency and growth rate for the l=1 diocotron mode are given, respectively, by the simple expressions Re{omega}={omega}{sub 0} and Im{omega}=({nu}{sub {ital en}}/{omega}{sub {ital ce}}){omega}{sub 0}. Here, {omega}{sub 0}={ital Nec}/{ital r}{sup 2}{sub {ital wB}}{sub 0}, where {ital r}{sub {ital w}} is the perfectly conducting wall radius, and {ital N}={integral}{ital d}{sup 2}{ital x}{ital n} is the number of electrons per unit axial length. This analysis suggests that a measurement of the oscillation frequency and growth rate for the l=1 diocotron mode can be used to infer {nu}{sub {ital en}}, and thereby serve as a sensor for the background neutral pressure. {copyright} {ital 1996 American Institute of Physics.}« less
  • Results are presented from an experimental investigation of the beam-plasma high-frequency (electron-electron) dissipative instability associated with the interaction between a long-pulse REB ({tau} = 100 {mu}s, E = 300 keV, I = 2-15 A) and a gas at a pressure of 0.02-8 torr in the absence of an external magnetic field. A description of the experimental device and the measurement technique (current, optical, and microwave diagnostics) are presented. The plasma was formed by the action of the beam itself in ionizing the neutral gas filling a metal chamber whose walls were coated with a radio-absorbent material during the course ofmore » the experiments. The critical current at which instability occurs was obtained as a function of the gas pressure and the distance over which the REB was transported. The spatial distribution of the microwave radiation emitted by the plasma when the instability was fully developed is presented. The effect on the instability was discovered of the intrinsic plasma microwave radiation reflected from the walls of the pressure chamber, which is related to the presence of feedback. The probable mechanism by which it arises are discussed. 26 refs., 8 figs.« less