A. Blagoev

Interaction processes with creation of fast electrons in the low temperature plasma

The methods and the results of investigations of the reactions in which electrons appear with energies surpassing the average electron distributions energy in a plasma are considered. Particular attention is paid to the plasma electron spectroscopy method, which combines the advantages of the elementary processes examination in a plasma with the possibilities of conventional electron spectroscopy. Data of the study of chemiionization reactions involving two excited rare gas atoms, Penning ionizations of atoms and molecules by the helium metastable atoms and quenching of excited inert gases and mercury atoms by the electrons are given. The influence of the processes of creating fast electrons on the plasma properties is discussed.

Beam Non-Uniformity Smoothing Using Density Valley Formed by Heavy Ion Beam Deposition in Inertial Confinement Fusion Fuel Pellet

We study the beam nonuniformity smoothing effect of radiation transport in the density valley formed by an ion-beam deposition in a heavy ion-beam inertial confinement fusion pellet by numerical simulations. The simulation results show that the radiation energy is confined in the density valley, and the beam nonuniformity can be smoothed out by the radiation transport along the density valley. In addition, an estimation for the Rayleigh-Taylor instability during the implosion phase is also presented.

Surface ionization wave in a plasma focus-like model device

A numerical particle in cell-Monte Carlo model of the breakdown in the plasma focus device simulates the development of an ionization wave sliding along the insulator. In order to validate this model a planar model device is created. The pictures of the discharges taken by a fast optical camera show that we have qualitative agreement between the model and the experimental observations.

Modeling of an axially inhomogeneous microwave argon plasma column at a moderate pressure

In this article, we present theoretical results for axial distributions of charged particles and excited atoms in an axially inhomogeneous microwave sustained argon plasma column at a pressure of 1.8 Torr. The model includes two self-consistently linked parts—electrodynamic and kinetic ones. It is found that the electron temperature is not a constant along the column length. The dependence of the mean power required for sustaining an electron–ion pair in the discharge on the electron number density is obtained taking into account different elementary processes. The theoretical results are in agreement with the available experimental data.

PIC-MCC method with finite element solver for Poisson equation used in simulation of the breakdown phase in dense plasma focus devices

Using PIC-MCC method for simulation of the breakdown of plasma focus device we obtained electron energy distribution function, spatial distributions of potential and charged particle densities. Studied is the first phase of the development of ionization process at pressures 133 - 931 Pa. Satisfactory agreement with experiment of the PF-1000 operation is observed for pressures in the range 665 - 931 Pa.

Chemi-ionization of ground-state Hg atoms by excited Ar atoms

The rate coefficients of the chemi-ionization collisions between and atoms are determined by optical absorption and probe measurements in decaying plasma. The corresponding cross section values at room temperature are as follows: A, A and A. These values are compared with the close-collision cross sections and the cross sections calculated by the optical model of interaction.

AXIAL DISTRIBUTIONS OF METASTABLE ATOMS AND CHARGED PARTICLES IN AN ULTRAHIGH FREQUENCY ARGON PLASMA COLUMN AT MODERATE PRESSURES

The axial distributions of electrons, atomic and molecular ions as well as metastable atoms in an argon ultrahigh frequency (UHF) discharge at a moderate pressure sustained by a traveling electromagnetic wave have been theoretically obtained. The dependence between the absorbed wave power and the electron density necessary for plasma modeling has been numerically derived by taking into account both direct and step‐wise ionization processes. The inclusion of step‐wise ionization process leads to a lower electron temperature comparing to that calculated under the assumption that only the direct ionization takes place. The results have been compared with the experimental data for an UHF argon plasma at 1.8 Torr. A better agreement is achieved when the ionization by metastable–metastable collisions is taken into account together with the step‐wise ionization.

A method for simultaneous determination of the diffusion coefficient of particles in gas media and their reflection coefficient at the wall

A method for simultaneous investigation of the diffusion of atoms and molecules in gas buffers and their reflection at the vessel walls is proposed. It is experimentally tested to obtain the diffusion coefficient of Mg atoms in neon and the coefficient of the reflection of these atoms from the metallic wall in the afterglow plasma of a pulsed hollow cathode at 320 K temperature. The diffusion coefficient value is compared with the theoretical calculation previously reported by Redko et al.

Superelastic collisions between slow electrons and excited Hg atoms

The rate coefficient of the superelastic electron-excited Hg 3P2 atom collision has been determined by plasma electron spectroscopy. At 0.2 eV electron temperature the rate value is beta e2=(2.9+or-1.2)10-8 cm3 s-1. Using this value the excitation cross section of Newman et al. (1985) is calibrated.

Investigation of the electron energy distribution function in a neon afterglow plasma

Abstract Probe measurements of the electron energy distribution function conducted in a neon afterglow plasma showed substantial deviations from a maxwellian distribution function in the high energy range. The differences result from Penning ionization and electron-metastable atom superelastic collisions.