Search

Calculations of the spectrum of eigen oscillations of an inhomogeneous ultracold plasma are presented both in the absence and in the presence of charge imbalance. The collective modes of these plasma oscillations are recorded in experiments as absorption resonances of a radio frequency electric field. It is shown that in the presence of friction of the electronic component, a discrete spectrum of plasma eigen oscillations is formed. The dependence of the frequency of these resonances on the plasma expansion time in the presence of a charge imbalance is obtained. There is good agreement with the experiments of different authors. [ABSTRACT FROM AUTHOR]

We discuss the influence of micro- and macro-fields on spectral lines of ions as it takes place for spatially inhomogeneous plasma. A distribution function of an electric field is obtained. The function accounts for inhomogeneity and non-neutrality of plasma. The results of calculations of this function for various regimes are presented. Experimental results for ultracold plasma are used to compare theory with experiment. Dependence of the absorption coefficient on the function is shown. These results may be useful for diagnostics of various types of plasmas. One of the methods of plasma diagnostics is the analysis of the influence of its electric field on the shape of the spectral lines of atoms and ions (the Stark effect). [ABSTRACT FROM AUTHOR]

We report the direct molecular dynamics simulation results of the ultracold two-component plasma expansion. Interaction between charges is described by Coulomb's law. The number of particles varies from 103 to 105. It is shown in this article that the expansion of the plasma begins with the evaporation of some of the electrons and with the transfer of their kinetic energy to the energy of the electric field. After that, the field increases the kinetic energy of the ions. An important result is the detection of the supersonic ion wave formation. On the basis of the calculation results, equations and self-similar solutions are obtained. General dependences on plasma parameters are determined, which are compared with experimental data. [ABSTRACT FROM AUTHOR]