scholarly journals Evaluation of ambipolar potential barrier in the gas dynamic trap by Doppler spectroscopy

2022 ◽  
Author(s):  
Andrej Lizunov ◽  
V V Maximov ◽  
Andrey Sandomirsky
Keyword(s):  
Potential Barrier ◽  
Diagnostic Technique ◽  
Potential Drop ◽  
Expansion Ratio ◽  
Gas Jet ◽  
Line Of Sight ◽  
Central Plane ◽  
Theoretical Understanding ◽  
Gas Dynamic ◽  
Doppler Spectroscopy

Abstract The recently developed Doppler spectroscopy diagnostic has been used to evaluate the height of the ambipolar potential barrier forming in the gas dynamic trap (GDT) plasma between the central cell and the region with a large magnetic expansion ratio beyond the mirror. The diagnostic technique based on the gas jet charge exchange target, allowed to measure the potential profile along the line of sight covering the radial range from the axis to the limiter. The on-axis potential drop was found to be 2.6÷3.1 in units of the central plane electron temperature, which supports the existing theoretical understanding of suppression of electron thermal conductivity in the GDT expander.

scholarly journals Акустические характеристики автоколебательного процесса, возникающего при взаимодействии сверхзвуковой недорасширенной струи с цилиндрической полостью

2020 ◽  
Vol 90 (5) ◽  
pp. 733
Author(s):  
К.Н. Волков ◽  
В.Н. Емельянов ◽  
А.В. Ефремов ◽  
А.И. Цветков
Keyword(s):  
Atmospheric Pressure ◽  
Acoustic Waves ◽  
Supersonic Jet ◽  
Cavity Resonator ◽  
Dynamic Structure ◽  
Gas Jet ◽  
Working Pressure ◽  
Gas Dynamic ◽  
Physical Pattern ◽  
Cylindrical Cavities

In high-pressure gas-jet emitters, the source of sound energy is kinetic energy of gas jet at supercritical pressure ratios between the working pressure and the atmospheric pressure. Under certain conditions, interaction of a supersonic jet with the resonator is accompanied by powerful self-excited oscillating process with the generation of acoustic waves into the environment and cavity resonator. A model of a self-excited oscillating process arising from the interaction of non-isobaric jet with semi-closed cylindrical cavities, allowing to distinguish typical elements of gas-dynamic structure of the forming flow, is considered. The physical pattern of the flow in the cavity of gas-jet emitter is discussed, and a study of the dependence of the characteristics of the self-excited oscillating process on the gas-dynamic and geometric parameters is performed.

scholarly journals Research in a physical model with the top blowing of a gas-dynamic head and jet parameters at blowing of a liquid bath through an annular coaxial slit nozzle

2018 ◽  
Author(s):  
S.I. Semykin ◽  
T.S. Golub ◽  
S.A. Dudchenko ◽  
V.V. Vakulchuk
Keyword(s):  
Physical Model ◽  
Dynamic Pressure ◽  
Liquid Bath ◽  
Gas Jet ◽  
Oxygen Absorption ◽  
Equivalent Diameter ◽  
Depth Of Penetration ◽  
Gas Dynamic ◽  
Dynamic Head ◽  
Purge Gas

The aim of the work is to study the physical model of the gas-dynamic head of a gas jet and the parameters of its penetration into the liquid bath of the converter when it flows out of the annular slotted tuyere. The studies were carried out on a «cold» stand on a scale of 1:30 to a 160-m converter (taking into account the criteria of geometrical and physical similarity) using water as a liquid simulating a molten metal,. The averaged values of the depth of penetration of the gas stream of the jet at various blowing parameters were estimated. It is noted that when the upper purge through a coaxial slit nozzle with an increase in the pressure of the purge gas, the dynamic pressure of the depth of penetration of the jet increases. The increase in dynamic pressure and the depth of the introduction of a gas jet leads to an increase in the degree of impact on the bath and an increase in the degree of oxygen absorption by the melt. It was shown that, all other things being equal, the operation of a coaxial slit differs by a large impulse of exposure to a liquid than when blowing through an equivalent diameter slot through one centrally located nozzle, especially at pressures above 0.15-0.3 MPa. The possibilities of increasing the efficiency of the top blowing of the converter bath are shown through the use of a slotted coaxial nozzle.

“Endurance”, a new NASA mission to gauge Earth’s polar wind ambipolar electric field

2020 ◽  
Author(s):  
Glyn Collinson ◽  
Alex Glocer ◽  
Robert Pfaff ◽  
Robert Michell ◽  
Aroh Barjatya ◽  
...  
Keyword(s):  
Electric Field ◽  
Fundamental Property ◽  
Potential Drop ◽  
Scientific Instrument ◽  
Polar Wind ◽  
Theoretical Understanding ◽  
Atmospheric Escape ◽  
Polar Caps ◽  
Light Ions ◽  
Field Lines

<p>Earth’s primary ionospheric loss process is the polar wind, which flows outwards along open magnetic field lines above our polar caps. One key component critical to the formation of this outflow is thought to be a weak ambipolar electric field. The potential drop resulting from this electric field is thought to assist terrestrial atmospheric escape since it reduces the potential barrier required for heavier ions (such as O<sup>+</sup>) to escape and accelerates light ions (such as H<sup>+</sup>) to escape velocity. Although a key component to atmospheric loss, Earth’s ambipolar electric field has never been measured due to its weak strength.</p><p> </p><p>We announce the NASA <em>Endurance</em> mission, launching in 2022, which will attempt to make the first direct in-situ observations of Earth’s ambipolar electric field. <em>Endurance</em> launch from Ny-Ålesund, Svalbard, and soar across the exobase to altitudes greater than 800km. The spacecraft will be equipped with a new type of scientific instrument which will enable the <em>Endurance</em> to measure the total electric potential drop below her. She will also be equipped with a full array of sensors that will enable the science team to self-consistently model the polar wind during the flight to test our current theoretical understanding of the physical processes which generate Earth’s ambipolar electric field.</p><p><em>Endurance</em> will perform groundbreaking discovery science, measuring a fundamental property of Earth for the first time: the strength of the ambipolar electric field generated by its ionosphere. The results will provide us with a better understanding of atmospheric escape at Earth, and why our planet is habitable.</p>

Diagnostic technique of gas jet for debris-free laser plasma EUV source

2000 ◽  
Author(s):  
Sergei V. Bobashev ◽  
Rene de Bruijn ◽  
Tatyana G. Kopytova ◽  
Yurii A. Kurakin ◽  
Alexander A. Schmidt ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Diagnostic Technique ◽  
Gas Jet

scholarly journals Numerical Analysis of Particle Trajectories in a Gas–Powder Jet during the Laser-Based Directed Energy Deposition Process

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2002
Author(s):  
Stanislav Stankevich ◽  
Nikolay Larionov ◽  
Ekaterina Valdaytseva
Keyword(s):  
Energy Deposition ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Gas Jet ◽  
Dynamic Parameters ◽  
Confined Space ◽  
Gas Dynamic ◽  
Directed Energy Deposition ◽  
Powder Particles ◽  
Directed Energy

Based on numerical solutions of the equation of motion of a particle in a gas jet modeled by the Reynolds-averaged Navier–Stokes equations, the features of transporting powder particles to the working zone of laser-based directed energy deposition are investigated. The propagation of a gas jet in a confined space in the presence of obstacles in the form of a substrate and a wall of a part is considered. A solution determining the gas-dynamic parameters of the jet is obtained, and the results of calculating its velocity field are presented. The influence of gas-dynamic parameters on the trajectories of the powder particles is analyzed. It is shown that these parameters determine the amount of model material involved in the formation of the geometry of the part.

Silicon Film Deposition Using a Gas-Jet Plasma-Chemical Method: Experiment and Gas-Dynamic Simulation

2018 ◽  
Vol 59 (5) ◽  
pp. 786-793
Author(s):  
R. G. Sharafutdinov ◽  
P. A. Skovorodko ◽  
V. G. Shchukin ◽  
V. O. Konstantinov
Keyword(s):  
Dynamic Simulation ◽  
Chemical Method ◽  
Silicon Film ◽  
Film Deposition ◽  
Gas Jet ◽  
Plasma Chemical ◽  
Gas Dynamic ◽  
Jet Plasma

Simulation of Multi-Gas Jet Flows by Use of Quasi Gas Dynamic Equation System

2021 ◽  
Vol 412 ◽  
pp. 73-82
Author(s):  
Evgeny V. Shilnikov ◽  
Tatiana G. Elizarova
Keyword(s):  
Density Ratio ◽  
Equation System ◽  
Gas Jet ◽  
Jet Flows ◽  
Good Efficiency ◽  
Gravity Forces ◽  
Gas Dynamic ◽  
Grid Convergence ◽  
Heavy Gas ◽  
Volume Method

In the present paper, we use the quasi gas dynamic (QGD) model together with a finite volume method for the simulation of a gas jet inflowing region filled with another gas in the presence of gravity forces. A flow picture for such flow strongly depends on the gases density ratio. Numerical simulations are held for a region filled with air under atmospheric pressure. Three variants of inflowing gas are considered: methane (light gas), butane (heavy gas) and helium (extremely light gas). A difference between flow pictures for these test cases is demonstrated. Results obtained with the presence of wind in the air are also compared. Grid convergence is established by use of different spatial meshes. Here, the the QGD model demonstrated good efficiency in modeling multi-gas jet flows. The calculations were also used for the adjustment of the numerical method parameters.

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