On the plasma quasineutrality under oscillatory confinement based on a nanosecond vacuum discharge

One of the main problems for inertial electrostatic confinement devices with electron injection is the space charge neutralization. This work is devoted to the analysis of the problem of plasma quasineutrality in the scheme of plasma oscillatory confinement based on nanosecond vacuum discharge (NVD). Electrodynamics modeling of the processes of aneutronic fusion of proton–boron showed that the plasma in the NVD, and especially on the discharge axis, really corresponds to a quasineutral regime, which is rather different from the well-known scheme of periodically oscillating plasma spheres (POPS). In this case, small oscillations in the NVD are a mechanism of resonant ion heating, unlike coherent compressions in the original POPS model. The scaling of the fusion power turns out to be close to the fusion scheme with POPS, but differs significantly in the values of the parameter of quasineutrality and the compression ratio.

Два вида структуры плазменного канала в импульсном разряде высокого давления в цезии

Simulation of the pulse-periodic high pressure cesium discharge is performed on the basis of equations of radiative gas dynamics. It is shown that in the discharge it is possible to implement two different types of structure of the plasma channel. At the beginning of the current pulse, the plasma discharge channel has a centered structure. At the same time, most of the plasma is concentrated near the discharge axis. The concentration of charged particles decreases along the radius.Then, if the current amplitude is large enough, during the plasma heating process, a transformation from the centered to the shell structure of the channel occurs. In this case, most of the plasma is concentrated on the periphery of the discharge and its concentration increases along the radius from the axis to the walls of the tube. It is shown that the transition from one channel structure to another occurs at a time when the specific heat capacity of the plasma near the axis reaches a deep minimum corresponding to a completely single ionized e-i plasma.

Генератор плазмы с магнитно-вихревой стабилизацией и возможности его применения

A design of a plasma generator, the parameters of the resulting plasma, and the possibilities of its use for the synthesis of nanosized powders and optical emission spectroscopy are described. The device operation is based on the arc discharge of alternating current (66 kHz) in an argon jet between water-cooled metal electrodes. The discharge is stabilized by a flow of isolating gas (helium, nitrogen, air) and an axial magnetic field. The gas flow is fed tangentially to the discharge axis. The plasma between the electrodes has the shape of a cylinder remote from the chamber walls. The temperature and electron concentration in the cross section of the plasma cylinder vary along the radius and take the maximum and minimum values.

MONTE CARLO SIMULATION OF POSITIVE CORONA DISCHARGE IN NITROGEN

The corona discharge commonly occurs in many engineering devices and processes. Their application is still largely based on empirical knowledge; accordingly it is very important to predict the physical properties of corona discharge by the appropriate numerical method. To control corona discharge properly by understanding of corona discharge properties at different discharge stages, time-varying characteristics of discharge which are resulted from electron collision with the gas molecules should be investigated. A numerical study of a corona discharge in nitrogen in a point to plane geometry is presented. It is obtained by Monte Carlo method and concerns space-time evolution of electron and ion densities as well as electric field distributions along the discharge axis.

Time and Space-Resolved Electron Densities in a Theta Pinch at Various Distances along the Discharge Axis

The influence of the finite length of the discharge coil on the axial behaviour of a theta pinch plasma column is investigated by measuring electron density profiles at various distances from the midplane of the coil along the discharge axis. The resulting line densities were then checked by an independent method. For a parallel trapped magnetic field it was possible in this way to measure end losses and also the collection rate of the contraction wave in the case of an antiparallel trapped magnetic field.

TRANSPORT OF MATERIAL IN SOURCES FOR SPECTROSCOPIC ANALYSIS

A study of the transport of material in the condensed d-c. spark discharge has been made, with the object of placing quantitative spectroscopic methods of analysis on a less empirical basis and thus permitting, (a) the recognition of certain conditions of source operation which lead to unreliable determinations, and (b) the determination of some of the criteria to be fulfilled for maximum precision in analytic measurements.Variations in the transport phenomena, as indicated by variations in the relative distributions of emitting atoms of various elements along the discharge axis on the addition of certain substances to a sample, appear to be closely connected with the ionization potentials and masses of the elements, and with the ionization potentials of other particles present in the discharge. The data indicate the necessity for the use of a spectroscopic buffer, and provide certain criteria for the choice of the buffer and of the internal standard element.The exact nature of the mechanism of transport is uncertain, but various considerations indicate that neither the motion of ions under the influence of the field nor diffusion in the ordinary sense is sufficient to account for observed features.