The conventional fluid description of multi-component plasma, supplemented by
an appropriate equation of state for the macroparticle component, is used to
evaluate the longitudinal sound velocity of Yukawa fluids. The obtained results
are in very good agreement with those obtained earlier employing the
quasi-localized charge approximation and molecular dynamics simulations in a
rather broad parameter regime. Thus, a simple yet accurate tool to estimate the
sound velocity across coupling regimes is proposed, which can be particularly
helpful in estimating the dust-acoustic velocity in strongly coupled dusty
(complex) plasmas. It is shown that, within the present approach, the sound
velocity is completely determined by particle-particle correlations and the
neutralizing medium (plasma), apart from providing screening of the Coulomb
interaction, has no other effect on the sound propagation. The ratio of the
actual sound velocity to its "ideal gas" (weak coupling) scale only weakly
depends on the coupling strength in the fluid regime, but exhibits a pronounced
decrease with the increase of the screening strength. The limitations of the
present approach in applications to real complex plasmas are briefly discussed.
Author(s): M. Lyon, S. D. Bergeson, A. Diaw, and M. S. Murillo
We report measurements and simulations of the time-evolving rms velocity distribution in an ultracold neutral plasma. A strongly coupled ultracold neutral Ca+ plasma is generated by photoionizing laser-cooled atoms close to threshold. A fraction of these ions is then promoted to the second ionizatio...
[Phys. Rev. E 91, 033101] Published Mon Mar 02, 2015
In this paper, we study the Dirac equation with a multiparameter exponential-type potential including two tensor interactions. We obtain the energy eigenvalues by using the Nikiforov-Uvarov method. The corresponding wave functions are obtained and expressed in terms of hypergeometric functions. The effects of the Coulomb and the Yukawa tensor interactions are also investigated numerically and discussed in detail.