Dusty plasma structures in He-Kr DC glow discharge

Complete text of publication follows. Ion drift in gas mixtures has certain properties that can be used to generate ion flows with desired characteristics. For example, when the field is strong, ion heating is significant, and there is a large difference in atomic weight between ions and atoms, the ion velocity distribution can be highly anisotropic. Ion distribution anisotropy can cause a substantial change in properties of dust structures in plasmas. Experiments on dusty plasma structures in glow discharge in mixtures of light and heavy gases (helium and argon), (helium and krypton) are performed, and results of numerical simulations of ion and electron drift in the mixture are presented. The model of electron-atom collisions is considered taking into account non-elastic collisions in electron energy balance. On the basis of numerical simulation the characteristics of electron velocity distribution function, the energy characteristics of electron drift in constant electric field in He-Kr discharge were tabulated. Values of drift velocity, average electron energy, Townsend characteristic energy, and average electron energy leading to excitation and ionization of atoms, ratio between energy losses in elastic and nonelastic collisions, Townsend ionization coefficient were obtained. For the experiment conditions calculations of dust particle charging characteristics are also conducted - values of an average dust charge, charge fluctuation, and number of the bounded ions are calculated. These calculations have shown that dust charging in a mix of a 'light' gas with a small additive of a 'heavy' gas and ions has a number of features which lead, in particular, to considerable (up to thousand times) increase of dust kinetic energy - this effect was observed in the experiments.