Formation Of Plasma Flow Research Articles

Formation of powerful plasma flow from substance of liquid electrolyte cathode

The process of plasma flow formation using an electric discharge with liquid electrolyte cathode in the power range (25–39) kW was experimentally investigated. The discharge was created inside the chamber with walls of refractory material at a distance of 20 cm between electrodes. Sodium chloride aqueous solutions with concentrations of 0.1–0.2 mol·l−1 were used as electrolyte. The optimal conditions are revealed under which the heat losses on the electrodes are reduced. Plasma stream with a mass rate of 1.0–1.7 g·s−1 was obtained.

Compression dynamics of quasi-spherical wire arrays with different linear mass profiles

Results of experimental studies of the implosion of quasi-spherical wire (or metalized fiber) arrays are presented. The goal of the experiments was to achieve synchronous three-dimensional compression of the plasma produced in different regions of a quasi-spherical array into its geometrical center. To search for optimal synchronization conditions, quasi-spherical arrays with different initial profiles of the linear mass were used. The following dependences of the linear mass on the poloidal angle were used: ml(θ) ∝ sin–1θ and ml(θ) ∝ sin–2θ. The compression dynamics of such arrays was compared with that of quasi-spherical arrays without linear mass profiling, ml(θ) = const. To verify the experimental data, the spatiotemporal dynamics of plasma compression in quasi-spherical arrays was studied using various diagnostics. The experiments on three-dimensional implosion of quasi-spherical arrays made it possible to study how the frozen-in magnetic field of the discharge current penetrates into the array. By measuring the magnetic field in the plasma of a quasi-spherical array, information is obtained on the processes of plasma production and formation of plasma flows from the wire/fiber regions with and without an additionally deposited mass. It is found that penetration of the magnetic flux depends on the initial linear mass profile ml(θ) of the quasi-spherical array. From space-resolved spectral measurements and frame imaging of plasma X-ray emission, information is obtained on the dimensions and shape of the X-ray source formed during the implosion of a quasi-spherical array. The intensity of this source is estimated and compared with that of the Z-pinch formed during the implosion of a cylindrical array.

A plasma Formation in Pulsed Coaxial Gun at Continuously Filling Regime

In work presented the results of researches of plasma flow formation and propagate in the electrodynamics pulsed gun. Experimental researches carried out on the basis of pulse plasma accelerator CPU-30 with a coaxial symmetric geometry electrodes. It was shown, that structure of the flow significantly depends on initial operating pressure of working gas, and specify for “continuously filled” regime. The data on dynamics of plasma acceleration, obtained in previous studies was refined. The role of plasma internal electric field and acceleration peculiarities on differ pressure of initial gas are discuss.

Plasma flow formation in a pulse plasma accelerator in continuous filling regime

Distribution of energy density of a plasma flow in the KPU-30 pulse coaxial accelerator at continuous gas filling has been investigated. The influence of discharge parameters on energy density at various pressures of the working gas is demonstrated. It is shown that the maximal plasma energy occurs in a pressure range of 0.02–0.05 torr. Distributions of energy density in the axial and radial directions are obtained. The focus point of the plasma flow is found and the plasma flow energy density at this point is measured.

Dynamics of plasma flow formation in a pulsed accelerator operating at a constant pressure

Features in the dynamics of plasma flow formation at a constant pressure in a pulsed coaxial accelerator have been studied. The temperature and density of electrons in a plasma bunch have been determined using a probe technique.

Microwave Oscillations in the Acceleration Channel of SPD-ATON Stationary Plasma Thruster

The parameters of microwave plasma oscillations in the acceleration channel of an SPD-ATON stationary plasma thruster have been measured. There is a stable correlation between the microwave intensity, on the one hand, and the magnetic field configuration in the region of plasma acceleration and the formation of plasma flow detached from the channel wall, on the other hand. The experimental data agree with the notion about the contribution of the electron scattering on microwave oscillations to the anomalous transverse conductivity of plasma in the acceleration channel.

Hot Plasma Flow Formation in Starforming Region

Hot Plasma Flow Formation in Starforming Region

On the Transition Region Explosive Events

We describe the properties of high-velocity and explosive events in the solar transition region determined from time series of data taken by the Transition Region and Coronal Explorer and the SUMER instrument on the Solar and Heliospheric Observatory (SOHO) simultaneously in several chromospheric and transition region lines co-aligned with high-resolution Michelson Doppler Imager (SOHO) magnetograms. We outline what the various features of these events can tell us about the heating mechanisms and formation of plasma flows. Our results strongly support the mechanism of hydrodynamic cumulation of energy associated with the cascade of shock waves produced by colliding and reconnecting flux tubes in the photospheric network (as recently discussed by T. D. Tarbell et al.). We find that the majority of the explosive events are caused by the explosive instability occurring in the presence of the behind-shock downflows, and less than 10% can be explained by the direct collision of shock fronts.

Very broad vacuum arc ion and plasma sources with extended large area cathodes

Two versions of vacuum arc sources for producing accelerated ion beams and plasma flows are described. The sources are distinguished by use of a dc vacuum arc discharge for plasma generation on the basis of a simple linear or coaxial plasma gun with extended large area (70 300 and 1500 cm2) cathodes and microparticle filtering system. The dc vacuum arc discharge combined with the diode extraction system enables us to use the single source for dc mode of plasma flow formation and repetitively pulsed mode of ion beam generation. Experimental and numerical results are presented on the repetitively pulsed accelerated ion beam formation in the vacuum arc sources with large area cathodes.

Transformation of axial vacuum-arc plasma flows into radial streams and their use in coating deposition

Radial filtered plasma flow formation in the annular gap between two oppositely directed rectilinear vacuum-arc erosion-plasma sources with magnetic focusing has been investigated. In both the opposing and aiding magnetic field configurations in the gap, the ion how density first increased to a certain maximum value (/spl sim/4 mA/cm/sup 2/ for Ti plasma) and then decreased with magnetic field strength, For this optimum condition the plasma losses during transformation of the axial flow into the radial flow were less than 20% in high vacuum. A uniform deposition rate of /spl sim/5 /spl mu/m/h (for droplet-free Al and Ti coatings) was achieved over the annular substrate surface of 1300 cm/sup 2/. (In case of conventional curvilinear filters this area is generally 10-20 cm/sup 2/).

Formation of plasma flow in a compact magnetoplasma compressor under conditions of increased cathode erosin

Formation of plasma flow in a compact magnetoplasma compressor under conditions of increased cathode erosin

3-D MHD simulation of the formation of spiral plasma flows during collision of two current loops

We present the results from a simulation of the collision between two current loops, by using a 3-D resistive MHD code. We consider two force-free current loops, as proposed by Gold and Hoyle (1960), which are obliquely approaching each other with angular momentum. It is shown that spiral plasma flows are produced after the collision of the two twisting current loops. This process of spiral plasma flow formation is important to understand the plasma mass flows observed in solar active regions.

Physical essence of erosional plasma formation and the formation of plasma flows by the action of different types of high-energy sources on absorbing condensed media

A study is made of erosional plasma processes occurring with the exposure of metals to a laser beam, a plasma, and a combination of the two. It is found that the ionization of the initially heated vapors is of a thermal nature, whether an erosional plasma is formed by an impulsive electrical discharge or a near-surface optical discharge.