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Title: Velocity space degrees of freedom of plasma fluctuations

 [1];  [2]
  1. Department of Physics and Astronomy, University of Iowa, 212 Van Allen Hall, Iowa City, Iowa 52242, USA
  2. Department of Physics and Astronomy, University of Iowa, 504 Van Allen Hall, Iowa City, Iowa 52242, USA
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 9; Related Information: CHORUS Timestamp: 2018-02-14 15:04:48; Journal ID: ISSN 1070-664X
American Institute of Physics
Country of Publication:
United States

Citation Formats

Mattingly, Sean, and Skiff, Fred. Velocity space degrees of freedom of plasma fluctuations. United States: N. p., 2017. Web. doi:10.1063/1.4996012.
Mattingly, Sean, & Skiff, Fred. Velocity space degrees of freedom of plasma fluctuations. United States. doi:10.1063/1.4996012.
Mattingly, Sean, and Skiff, Fred. 2017. "Velocity space degrees of freedom of plasma fluctuations". United States. doi:10.1063/1.4996012.
title = {Velocity space degrees of freedom of plasma fluctuations},
author = {Mattingly, Sean and Skiff, Fred},
abstractNote = {},
doi = {10.1063/1.4996012},
journal = {Physics of Plasmas},
number = 9,
volume = 24,
place = {United States},
year = 2017,
month = 9

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on September 29, 2018
Publisher's Accepted Manuscript

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  • We use a classical dynamical theory with shape degrees of freedom to describe deep inelastic scattering of heavy ions, and include thermal fluctuations by means of the Fokker-Planck equation. The degrees of freedom allow for neck formation, mass transfer, and stretching of the two-nucleus system. Inertias are calculated for these degrees of freedom, and dissipative and conservative forces are used. Fluctuations are calculated by considering the second moments of the distribution and determining a temperature from the excitation energy at each time. We calculate distributions in final energy, angle, charge, and mass, including some double differential cross sections. Results aremore » in good agreement with data.« less
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  • Angle and recoil velocity distributions have been measured for the scattering of CS/sub 2/ molecules from a crossed beam of rare gas atoms. Nozzle expansion and H/sub 2/ seeding provided cooling of CS/sub 2/ molecules and narrow collision energy distributions, ranging from E = 8.1 to 30.7 kJ/mole for Xe + CS/sub 2/. Angular distributions of CS/sub 2/ were measured by rotating the beam sources. The scattered beam was modulated with a pseudorandom binarysequence, and the flight-time distribution of the scattered molecules was calculated from the cross correlated signal with an on-line computer. The measured velocity--angle contour plots show thatmore » the translational to vibrational excitation cross section is small compared with the translational to rotational excitation cross section and that the latter is strongly peaked in the forward direction. The CS/sub 2/ angle and recoil velocity distributions are strongly coupled and the rotational excitation reaches a maximum at intermediate values of the c.m. scattering angle; this, together with the strong forward peaking of the cross section, suggests that a direct mechanism is responsible for the observed energy transfer. Further analysis of the data using only the most probable scattering energy shows that a substantial amount of energy, ranging from maxima of approx. 18% for Ne to approx. 45 to 50% for Ar, Kr, and Xe, is transferred from relative translation to rotational excitation of the CS/sub 2/ molecules; that the fractional energy losses for Xe+CS/sub 2/ are comparable for E = 17.2 and 30.7 kJ/mole, but considerably less at 8.1 kJ/mole; that both the rotational excitation cross sections and the fractional energy losses at comparable collision energies follow the relations Kr approx. = Xe > or approx = Ar > Ne; and that the scattering angle for maximum energy loss is smallest for Kr and largest for Ne and Ar and increases somewhat with increasing collision energy.« less
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