Study of moving striations in plasmas. I. Measurement of the phase between the variations of several plasma parameters

1968 ◽  
Vol 46 (16) ◽  
pp. 1787-1793 ◽  
Author(s):  
Michel G. Drouet ◽  
Miloš Šicha
Keyword(s):  
Light Intensity ◽  
Electric Field ◽  
Electron Temperature ◽  
Discharge Current ◽  
Plasma Potential ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Continuous Waves ◽  
Slow Moving ◽  
Made In

The phases between the variations of electron density, electron temperature, plasma potential, electric field, and light intensity have been measured in slow-moving striations in a neon discharge for different values of the discharge current. The reported measurements were made in moving striations artificially excited in the form of both continuous waves and wave of stratification.

scholarly journals Diagnostics of dusty plasma properties in planar magnetron sputtering device

2019 ◽  
Vol 13 (26) ◽  
pp. 64-75
Author(s):  
Qusay A. Abbas
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Discharge Current ◽  
Plasma Potential ◽  
Dust Particles ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Radial Profiles ◽  
Planar Magnetron ◽  
Radial Axis

The effect of Al dust particles on glow discharge regions, dischargevoltage, discharge current, plasma potential, floating potential,electron density and electron temperature in planar magnetronsputtering device has been studied experimentally. Four cylindricalLangmuir probes were employed to measure plasma parameters atdifferent point on the radial axis of plasma column. The resultsshows the present of Al dust causes to increase the discharge voltageand reduce the discharge current. There are two electron groups inthe present and absent of Al dust particles. The radial profiles ofplasma parameters in the present of dust are non- uniform. Thefloating potential of probe becomes more negatively while theplasma potential becomes positive when the dust immersed intoplasma region. The electron density increases in the present of dustparticle which lead to decreases the electron temperature.

Study of moving striations in plasmas. V. A study of the saturation process in large amplitude moving striations

1969 ◽  
Vol 47 (7) ◽  
pp. 779-785 ◽  
Author(s):  
Richard Bolton ◽  
Miloš Šícha ◽  
Michel G. Drouet
Keyword(s):  
Electric Field ◽  
Electron Temperature ◽  
External Electric Field ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Potential Drop ◽  
Plasma Potential ◽  
Temperature Plasma ◽  
Current Limit

Measurements made near the Pupp current limit for the existence of moving striations in neon illustrate the process of saturation of moving striations as the column amplification increases. The measurements show that the nature of the striations changes from the characterization of Pekárek for small amplitude to that of Nedospasov for large amplitude as the plasma potential variation in the striation approaches the potential drop of the external electric field per striation wavelength. Measurements of the relative phases of electron temperature, plasma potential, and luminous intensity for striations near the Pupp current limit are presented.

scholarly journals Effect of the gas puff location on the divertor plasma properties in COMPASS tokamak

2020 ◽  
Vol 1492 (1) ◽  
pp. 012003
Author(s):  
M Dimitrova ◽  
M Tomes ◽  
Tsv Popov ◽  
R Dejarnac ◽  
J Stockel ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Vacuum Chamber ◽  
Plasma Potential ◽  
Saturation Current ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Low Field ◽  
Saturation Current Density ◽  
Deuterium Gas

Abstract Langmuir probes are used to study the plasma parameters in the divertor during deuterium gas puff injection on the high- (HFS) or low-field sides (LFS). The probe data were processed to evaluate the plasma potential and the electron temperatures and densities. A difference was found in the plasma parameters depending on the gas puff location. In the case of a gas puff on the LFS, the plasma parameters changed vastly, mainly in the inner divertor – the plasma potential, the ion saturation-current density and the electron temperature dropped. After the gas puff, the electron temperature changed from 10-15 eV down to within the 5-9 eV range. As a result, the parallel heat-flux density decreased. At the same time, in the outer divertor the plasma parameters remained the same. We thus concluded that using a gas puff on the LFS will facilitate reaching a detachment regime by increasing the density of puffed neutrals. When the deuterium gas puff was on the HFS, the plasma parameters in the divertor region remained almost the same before and during the puff. The electron temperature decreased with just few eV as a result of the increased amount of gas in the vacuum chamber.

scholarly journals Charged Particle Oscillations in Transient Plasmas Generated by Nanosecond Laser Ablation on Mg Target

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Maricel Agop ◽  
Ilarion Mihaila ◽  
Florin Nedeff ◽  
Stefan Andrei Irimiciuc
Keyword(s):  
Charged Particle ◽  
Laser Ablation ◽  
Particle Density ◽  
Plasma Potential ◽  
The Self ◽  
Tunneling Effect ◽  
Nanosecond Laser ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Laser Produced Plasma

The dynamics of a transient plasma generated by laser ablation on a Mg target was investigated by means of the Langmuir probe method and fractal analysis. The empirical data showcased the presence of an oscillatory behavior at short expansion times (<1 μs) characterized by two oscillation frequencies and a classical behavior for longer evolution times. Space- and time-resolved analysis was implemented in order to determine main plasma parameters like the electron temperature, plasma potential, or charged particle density. In the motion fractal paradigm, a theoretical model was built for the description of laser-produced plasma dynamics expressed through fractal-type equations. The calibration of such dynamics was performed through a fractal-type tunneling effect for physical systems with spontaneous symmetry breaking. This allows both the self-structuring of laser-produced plasma in two structures based on its separation on different oscillation modes and the determination of some characteristics involved in the self-structuring process. The mutual conditionings between the two structures are given as joint invariant functions on the action of two isomorph groups of SL(2R) type through the Stoler-type transformation, explicitly given through amplitude self-modulation.

Stability and spatial characterization of electron cyclotron resonance processing plasmas

1991 ◽  
Vol 69 (3-4) ◽  
pp. 195-201 ◽  
Author(s):  
P. K. Shufflebotham ◽  
D. J. Thomson
Keyword(s):  
Electron Temperature ◽  
Plasma Density ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Plasma Potential ◽  
Electron Cyclotron ◽  
Temperature Plasma ◽  
Ecr Plasma ◽  
The Stability ◽  
System Variables

This paper presents preliminary measurements of the spatial variation of the plasma density, electron temperature, plasma potential, and floating voltage within a divergent magnetic field electron cyclotron resonance (ECR) plasma processing reactor. The measurements are performed using an orbital-motion-limited cylindrical Langmuir probe designed specifically for use in these plasmas. A brief discussion of the stability and uniformity of divergent field plasmas in general, and qualitative techniques for the diagnosis of these properties, is also given. It was found that these plasmas generally occurred in distinct "modes," characterized by unique shapes and dependences on system variables, and between which discontinuous, noisy, and often bistable transitions occurred. Axially resolved probe measurements performed under ECR conditions showed that the plasma density exhibited a broadly peaked profile, while the electron temperature showed a sharp peak at ECR. The differences in these profiles leads to three qualitatively different plasma regions available for use in ECR processing. The variation of the plasma potential explains the origin of the axial ion beams that commonly occur in these systems.

Radialverteilung der Nachleuchte-Lichtintensität im Stickstoff / Radial Distribution of the Light-intensity in Nitrogen Afterglow

1976 ◽  
Vol 31 (11) ◽  
pp. 1431-1432 ◽  
Author(s):  
P. Kocian
Keyword(s):  
Light Intensity ◽  
Bessel Function ◽  
Radial Distribution ◽  
Discharge Current ◽  
Pressure Range ◽  
Band System ◽  
Radial Profile ◽  
Positive Band ◽  
Made In

Abstract Radial Distribution of the Light-intensity in Nitrogen Afterglow The radial distribution of the first positive band system in nitrogen afterglow in dependence on the discharge current and on the pressure has been investigated. The measurements were made in the pressure range 0.06 torr-6 torr. It has been found that the radial profile of the intensity fol-lows approximately the square of the J0 Bessel function.

Solitary Langmuir waves in two-electron temperature plasma

2013 ◽  
Vol 80 (3) ◽  
pp. 405-415
Author(s):  
V. V. Prudkikh
Keyword(s):  
Electron Temperature ◽  
Acoustic Waves ◽  
Low Frequency ◽  
Langmuir Wave ◽  
Wave Interaction ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Langmuir Waves ◽  
Peak Structure ◽  
Langmuir Soliton

Nonlinear interaction of Langmuir and ion-acoustic waves in two-electron temperature plasma is investigated. New integrable wave interaction regime was discovered, this regime corresponds to the Langmuir soliton with three-hump amplitude, propagating with a speed close to the ion–sound speed in the conditions of strong non-isothermality of electronic components. It was discovered that besides the known analytical solution in the form of one- and two-hump waves, there exists a range of solutions in the form of solitary waves, which in the form of envelope has multi-peak structure and differs from the standard profiles described by hyperbolic functions. In case of fixed plasma parameters, different group velocities correspond to the waves with different number of peaks. It is found that the Langmuir wave package contains both even and uneven numbers of oscillations. Low-frequency potential here has uneven number of peaks. Interrelation of obtained and known earlier results are also discussed.

Langmuir solitons in a two-temperature plasma

1981 ◽  
Vol 26 (2) ◽  
pp. 309-316 ◽  
Author(s):  
B. Buti ◽  
M. Y. Yu
Keyword(s):  
Electric Field ◽  
Electron Temperature ◽  
Solitary Waves ◽  
Sound Speed ◽  
Finite Amplitude ◽  
Field Amplitude ◽  
Temperature Plasma ◽  
Electric Field Amplitude ◽  
Langmuir Solitons ◽  
Two Temperature

The existence of finite-amplitude Langnwir solitary waves in a two-electron-temperature plastia is investigated. A now type of soliton, in which the density depression and the electric field amplitude scale in the same manner, and which travels at the effective sound speed, has been found.

Study of plasma parameters in a staged pinch device using current-stepping technique

2009 ◽  
Vol 75 (4) ◽  
pp. 509-516
Author(s):  
FARAH DEEBA ◽  
KAMALUDDIN AHMED ◽  
MAHNAZ QADAR HASEEB ◽  
ARSHAD M. MIRZA
Keyword(s):  
High Temperature ◽  
Pulse Duration ◽  
Discharge Current ◽  
High Density ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Alternative Approach ◽  
Long Pulse ◽  
Z Pinch ◽  
A Current

AbstractThe implosion dynamics and fusion parameters of a high density D-T fibre plasma driven by Z-pinch with current stepping technique is investigated. Our numerical results demonstrate that a current-stepping technique reduces the minimum pinch radius, and as a result high density, high temperature plasma can be formed. Thus a staged pinch device with current-stepping technique can be used as an alternative approach to achieve fusion conditions with relatively small values of discharge current and with a long pulse duration.

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