V. I. Vladimirov

Dust particles in a nuclear-induced plasma

Abstract For the first time we have performed experiments in a nuclear-induced plasma with micron-sized dust macroparticles injected into it. The plasma was formed in atmospheric air by alpha-particles and fission fragments of 252 Cf as well as by beta-active particles. In both cases ordered liquid-type structures of dust particles levitating in the interelectrode space were observed.

Coulomb stable structures of charged dust particles in a dynamical trap at atmospheric pressure in air

A mathematical simulation of a dust particles behavior in the electrodynamic linear quadrupole trap with closing end electrodes allowed us to reveal several features of the phenomena. Regions of stable confinement of a single particle, in dependence of frequency and charge-to-mass ratio, were determined. With an increase of the mediums dynamical viscosity, the region for confining charged particles by the trap becomes wider. We obtained values of the maximum quantities of charged particles confined by the trap at atmospheric pressure in air. Firstly, we presented observations of ordered Coulomb structures of charged dust particles obtained in the quadrupole trap in air at atmospheric pressure. The structures consisted of positively charged oxide aluminum particles 10?15??m in size and hollow glass microspheres 30?50??m in diameter. The ordered structure could contain particles of different sizes and charges. The trap could confine a limited number of charged particles. The ordered structures of charged micro-particles obtained in the experiments can be used to study Coulomb systems without neutralizing the plasma background and action of ion and electron flows, which are always present in non-homogeneous plasma.

Dust grain charging in the nuclear-induced plasma

Abstract For the first time we have performed experiments in the nuclear-induced neon plasma with micron-sized dust grains injected into it and calculated grain electric charges in a single track of 252 Cf fission fragment and in electron and ion drift flows. Levitating ordered structures of dust grains were observed. The results of calculations are in good agreement with the experiment.

Confinement of the charged microparticles by alternating electric fields in a gas flow

This paper presents the simulation and experimental results of charged microparticles dynamics in electrodynamic traps in a gas flow at atmospheric pressure. For the first time the capture and confinement of charged microparticles in a linear Paul trap has been experimentally confirmed at atmospheric pressure in gas flows. The regions of the microparticle, linear Paul trap and gas flow parameters needed for microparticle confinement have been obtained and experimentally tested.

The corona discharge in nuclear excited plasma as a way of obtaining ordered dust particle structures

A model of a corona discharge in a nuclear excited dust plasma at the pressures of 1–100 atm is proposed. The distributions of the electric field and current-voltage characteristics of a corona discharge in a nuclear-excited dust plasma are found for a particular cylindrical geometry case at different methods of corona-producing electrode positioning. The conditions for the existence of a stationary corona discharge are obtained. A mathematical model describing the behavior of dust particles in a nuclear plasma that allows taking into account the key physical processes occurring in a nuclear-excited dust plasma is considered. The analyzed plasma properties are as follows: (1) shielding of the Coulomb forces of the interaction between dust particles, (2) the energy exchange and the stochastic character of the dust particle interaction with a buffer gas and ambient plasma, and (3) strong spatial inhomogeneity of the nuclear-excited plasma. The use of a corona discharge in a nuclear-excited plasma will make it possible to ensure stability of plasma-dust structures and more efficient conversion of the nuclear energy into laser radiation.

Dynamic vortex dust structures in a nuclear-track plasma

Results are presented from Monte Carlo calculations of the electric charge on dust grains in a plasma produced during the slowing down of radioactive decay products of californium nuclei in neon. The dust grain charging is explained as being due to the drift of electrons and ions in an external electric field. It is shown that the charges of the grains depend on their coordinates and strongly fluctuate with time. The time-averaged grain charges agree with the experimental data obtained on ordered liquid-like dust structures in a nuclear-track plasma. The time-averaged dust grain charges are used to carry out computer modelling of the formation of dynamic vortex structures observed in experiments. Evidence is obtained for the fact that the electrostatic forces experienced by the dust grains are potential in character. The paper is supplemented by a video clip showing the typical dynamics of the simulated vortex dust structure.

Dust grain charges in a nuclear-track plasma and the formation of dynamic vortex dust structures

Results are presented from Monte Carlo calculations of the electric charge of dust grains in a plasma produced during the slowing down of the radioactive decay products of californium nuclei in neon. The dust grain charging is explained for the first time as being due to the drift of electrons and ions in an external electric field. It is shown that the charges of the grains depend on their coordinates and strongly fluctuate with time. The time-averaged grain charges agree with the experimental data obtained on ordered liquidlike dust structures in a nuclear-track plasma. The time-averaged dust grain charges are used to carry out computer modeling of the formation of dynamic vortex structures observed in experiments. Evidence is obtained of the fact that the electrostatic forces experienced by the dust grains are potential in character.

Capture and retention of charged dust particles in electrodynamic traps

The conditions of capture and retention of charged dust particles in linear Paul traps in air at atmospheric pressure in a wide range of parameters characterizing both dynamic traps and confined particles have been found by means of Brownian dynamics. It is shown that the viscosity of a gaseous medium strongly affects capture and retention of dust particles. The simulation results are in agreement with the experimental data on the creation and retention of a stable Coulomb cluster of charged dust particles in a quadrupole trap.

Vortex Dust Structures in the Track Plasma of a Proton Beam

Results are presented from experimental and theoretical investigations of the behavior of dust grains in a track plasma produced by a beam of accelerated protons. The dynamic ordered dust structures in a proton-beam-produced plasma are obtained for the first time. The processes leading to the formation of such structures are simulated numerically. The experimentally obtained dynamic vortex dust structures in a track plasma of a proton beam are explained theoretically, and the theoretical model developed to describe such a plasma is verified experimentally. Numerical investigations carried out by the method of Brownian dynamics made it possible to qualitatively explain the characteristic features of the formation of vortex dust structures.

Dust vortices, clouds, and jets in nuclear-induced plasmas

The collective movement of dust particles in a plasma formed during deceleration of decay products of californium nuclei in neon is investigated experimentally. For the first time, compact vortex structures containing a large number of coagulating dust particles and dense dust clouds evolving in time are observed. Dust formations have clearly defined boundaries and particles in them form ordered liquid-type structures. Under steady-state conditions, dust structures exist from several minutes to hours. An increase in the voltage applied to the high-voltage electrode leads to the formation of dust particle jets. A change in the electric field configuration transforms the structures from one type to another. A strong recombination of electrons and ions at dust particles is observed. The momentum transfer from ions drifting in an external field to gas molecules is studied using the Monte Carlo method. It is shown that the transferred momentum is so large that it may cause a gas flow. The characteristic features of vortex flow in neon and in air are explained.