Radial distribution of the electron concentration in a rotating plasma with the help of an interferometer

Results of experiments on the investigation of a plasma rotating in crossed electric and magnetic fields are presented. The radial electron concentration distributions in a nitrogen plasma at pressures varying from 8·10^–2 to 3·10^–1 mm Hg are obtained with the help of a 3.39 m laser interferometer. The effect of the magnitude of the magnetic field on the form of the radial distribution is determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 72–75, January, 1982.     

Radial distribution of plasma density in the positive column of thehigh-current stationary glow discharge

A model is presented which describes the radial distributions of the plasma density, electric potential, current density, and magnetic field in the positive column of a stationary glow discharge not in contact with the longitudinal walls of the discharge chamber. In this model, the compression of the positive column is provided by the azimuthal magnetic field created by the discharge current. The value of, the discharge current is obtained for the case where charged-particle diffusion is balanced by the actions of the radial electric field and the magnetic pinch effect. The radial distributions of plasma parameters are also calculated for the case of high-current glow discharges where charged-particle diffusion can be ignored     

Radial inhomogenity of plasma parameters in a low-pressure inductive RF discharge

This work is devoted to systematic investigation into the radial dependence of the plasma parameters of a low-pressure inductive radio-frequency (RF) discharge on pressure within a wide range of 0.8–1 Torr. Experimental results that were obtained under the considered pressures make it possible to analyze the patterns of the changes in plasma parameters upon both a nonlocal mode of discharge and a transition from a nonlocal to local mode of the RF power input. Discharges in helium, neon, argon, and krypton were considered. Experimental data were compared to the results of the numerical simulation of the inductive RF discharge using the particle-in-cell (PIC) method.     

等离子体羽中氧原子的光谱强度分布

大气压等离子体羽放电产生的低温等离子体由于不需要真空装置,可以对复杂材料进行三维处理等,在工业上具有广泛的应用前景。本工作利用等离子体针放电装置在大气压空气中产生了稳定的等离子体羽。通过光谱测量,发现等离子体羽发射谱中存在777.5和844.6nm的氧原子谱线。这表明在大气压空气放电中产生了具有高化学活性的氧原子。通过光谱学方法研究了氧原子谱线强度的空间分布,发现靠近电极处氧原子谱线强度远大于其他位置。为了对这一现象进行解释,利用光电倍增管对等离子体羽的发光信号进行了空间分辨测量,发现靠近电极处发光信号宽度远大于其他位置的发光信号宽度。这些结果对大气压空气等离子体羽在杀菌消毒等领域的应用具有重要意义。     

Radial extraction of ions from a plasma column obtained by reflex discharge

We describe here a system extracting ions perpendicularly to the magnetic field which confines the plasma. This system uses an efficient magnetic screen and a lens focusing the ions onto a quadrupole mass spectrograph. We give results in H₂-plasma.     

Distribution of plasma parameters in the cathode region of a glow discharge in nitrogen

The experiments with a low-pressure glow discharge in nitrogen indicate the formation of a potential well for thermal electrons and the sign reversal of the electric field near the concentration maximum of the near-cathode plasma. Depending on reduced discharge length pL, one or two field reversal points exist, which correlate with the sign of the anode fall (negative or positive, respectively).     

Effects of electron concentration in the plasma of an arc discharge on the relative population of the displaced levels of the copper atom

The relative populations of the e⁴Dj levels of copper (which differ in autoionization probability) are examined as functions of election concentration N_e; it is found that the latter can be deduced from the relative intensities of the transitions from the levels.     

Radial distribution of hydrogen atoms in H 2 plasma

The radial intensities of the H _α and H ₂ Fulcher α (d ³Π_u − a ³Σ_g) system spectral lines were used to obtain the radial distribution of hydrogen atoms in H ₂ plasma discharge. We have obtained new equations in order to describe the distribution of atoms in molecule discharges. Abel’s integral equation has been solved by Tikhonov’s regularization procedure. Model functions have been introduced to examine the limitations in the applicability of this method. An estimation of the degree of dissociation in the radial direction has been obtained.     

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采用粒子模拟与蒙特卡罗模型相结合(PIC/MCC)的方法,建立了氮分子气体辉光放电自洽的混合模型,其中带电粒子在电场中的运动及其产生的自洽场由PIC方法的静电模型描述,粒子间的碰撞过程由MC方法描述。模拟了放电过程及带电粒子(e、N2+、N+)在整个放电空间的行为及与之对应的自洽电场和电势的分布,通过计算带电粒子在负辉区的几率分布函数,讨论了带电粒子(e、N2+、N+)在负辉区的行为和分布特征。计算的分子离子密度与实验结果一致。     

Radial distribution of cesium plasma produced by resonance absorption

Radial distribution of Cs plasma produced by the resonance absorption has been obtained. The distribution has a minimum at the center of the tube and differs from one for the discharge plasma.     

Variations in the electron energy distribution function in discharge plasma of a unipolar gas breakdown

It is experimentally demonstrated that the electron energy distribution function (EEDF) and electron density in plasma of a little-studied pulse discharge of a unipolar gas breakdown (UGB) significantly vary in time. The revealed behavior of its plasma parameters is explained based on the proposed physical model of a UGB discharge.     

Radial changes of the energy distribution function in the argon flowing afterglow plasma

With the help of a Langmuir probe movable both in the axial and in the radial direction, the second derivative of the probe characteric has been determined. Depending on the flowing tube radius, different types of the electron energy distribution function have been found for three distances from the argon dc discharge.Presented at Colloquium on Plasma Physics Topics Common to the Laboratory and the Space Plasma Research, September 10–14, 1984, Horská Kvilda, Czechoslovakia.