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Coupling of Charged Particles Via Coulombic Interactions: Numerical Simulations and Resultant Kappa-Like Velocity Space Distribution FunctionsA parametric study is performed using the electrostatic simulations of Randol and Christian (2014) in which the number density, n, and initial thermal speed, theta, are varied. The range of parameters covers an extremely broad plasma regime, all the way from the very weak coupling of space plasmas to the very strong coupling of solid plasmas. The first result is that simulations at the same Lambda(sub D), where Lambda(sub D) is the plasma coupling parameter, but at different combinations of n and theta, behave exactly the same. As a function of Lambda(sub D), the form of p(v), the velocity distribution function of v, the magnitude of v, the velocity vector, is studied. For intermediate to high D, heating is observed in p(v) that obeys conservation of energy, and a suprathermal tail is formed, with a spectral index that depends on Lambda(sub D). For strong coupling (Lambda(sub D) much > 1), the form of the tail is v5, consistent with the findings of Randol and Christian (2014). For weak coupling (Lambda(sub D much <1), no acceleration or heating occurs, as there is no free energy. The dependence on N, the number of particles in the simulation, is also explored. There is a subtle dependence in the index of the tail, such that v5 appears to be the N approaches infinity limit.
Document ID
20170004648
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Randol, Brent M.
(Maryland Univ. College Park, MD, United States)
Christian, Eric R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
May 19, 2017
Publication Date
March 25, 2016
Publication Information
Publication: Journal of Geophysical Research: Space Physics
Volume: 121
Issue: 3
ISSN: 2169-9380
e-ISSN: 2169-9402
Subject Category
Plasma Physics
Space Sciences (General)
Report/Patent Number
GSFC-E-DAA-TN40758
Distribution Limits
Public
Copyright
Other

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