Coupling strength in Coulomb and Yukawa one-component plasmas
- Christian-Albrechts-Universität zu Kiel, Institut für Theoretische Physik und Astrophysik, Leibnizstraße 15, Kiel 24098 (Germany)
- Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
In a non-ideal classical Coulomb one-component plasma (OCP), all thermodynamic properties are known to depend only on a single parameter—the coupling parameter Γ. In contrast, if the pair interaction is screened by background charges (Yukawa OCP) the thermodynamic state depends, in addition, on the range of the interaction via the screening parameter κ. How to determine in this case an effective coupling parameter has been a matter of intensive debate. Here we propose a consistent approach for defining and measuring the coupling strength in Coulomb and Yukawa OCPs based on a fundamental structural quantity, the radial pair distribution function (RPDF). The RPDF is often accessible in experiments by direct observation or indirectly through the static structure factor. Alternatively, it is directly computed in theoretical models or simulations. Our approach is based on the observation that the build-up of correlation from a weakly coupled system proceeds in two steps: First, a monotonically increasing volume around each particle becomes devoid of other particles (correlation hole), and second (upon further increase of the coupling), a shell structure emerges around each particle giving rise to growing peaks of the RPDF. Using molecular dynamics simulation, we present a systematic study for the dependence of these features of the RPDF on Γ and κ and derive a simple expression for the effective coupling parameter.
- OSTI ID:
- 22403304
- Journal Information:
- Physics of Plasmas, Vol. 21, Issue 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Onsager molecules for the Yukawa potentials: Screening potentials and the Jancovici coefficient in strongly coupled electron-screened plasmas
On the existence of vapor-liquid phase transition in dusty plasmas