Two-Dimensional Self-Consistent Radio-Frequency Plasma Simulations Relevant to the Gaseous Electronics Conference Rf Reference Cell

Lymberopoulos, Dimitris P.; Economou, Demetre J.

doi:10.6028/jres.100.036

Cited by 137 publications

(109 citation statements)

References 49 publications

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“…Following the procedure described in Ref. [33], the boundary conditions at With the zero thermal flux at the discharge walls usually considered [28,32,34], the boundary condition for the electron energy flux at the walls …”

Section: Charged Particle Descriptionmentioning

confidence: 99%

Magnetic filter operation in hydrogen plasmas

Kolev

Lishev

Shivarova

et al. 2007

Plasma Phys. Control. Fusion

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Abstract. Fluid-plasma model description of the operation of a magnetic filter for electron cooling in gas-discharge plasmas is presented in the study. Directed to the use of weak magnetic fields in the sources of negative hydrogen ion beams for additional heating of fusion plasmas, hydrogen discharges have been considered. The numerical results obtained within a 2D model are stressed. The 1D model presented aims at showing main trends whereas the results obtained within the 3D model, also developed, come to confirm the 2D-model description. The models outline importance of the transport phenomena: electron-energy and charged-particle fluxes. Reduction of the thermal flux across the magnetic field together with thermal diffusion and diffusion, acting in a combination, are in the basis of the electron cooling and of the spatial distribution of the electron density. Effects due to the ) ( B E × -drift and to the diamagnetic drift form the fine spatial structure of the plasma-parameter variations. IntroductionThe development of sources of negative ion beams for fusion plasma heating by neutral beam injection [1-4] is one of the stimuli motivating the active research on low-pressure hydrogen discharges. In general, the sources of negative hydrogen ions with volume-production based processes as well as the hybrid sources where surface production is employed are tandem-type sources with a construction ensuring space separation of regions of high and low electron temperature [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Thus, electron cooling in the discharge is needed and this is provided by a magnetic filter.The magnetic filter is a localized transverse magnetic field. Its effect for cooling the electrons has been proved both experimentally [3,6,7,13,[20][21][22][23][24][25][26], by probe diagnostics and measurements of the current density of the extracted negative ions, and theoretically [6][7][8][9][10][11][12]15,27] by modelling and discussions on the mechanisms governing the operation of the filter. The fluid-plasma models [6][7][8][9][10]15] of the magnetic filter involve importance of the transport processes. However, the different models stress different aspects as mechanisms of the filter operation: (i) reduction of the electron mobility and of the diffusion in magnetized plasmas acting in a combination with the temperature dependence of the Coulomb collision frequency, the latter considered as a factor ensuring lower diffusion of the hot electrons; (ii) thermal conductivity effects, again acting together with Coulomb collisions; (iii) importance of the Lorentz force showing evidence due to cancelled effects of the -) ( B E × and diamagnetic drifts; (iv) importance of the diamagnetic drift; (v) diffusion acting together with elastic electron-neutral collisions. Both 1D and 2D models have been developed, however, as it has been usually stressed, 2D models are needed for proper description of the problem. Due to the complexity of the description, simplifying assumptions, like neglecting of col...

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Section: Charged Particle Descriptionmentioning

confidence: 99%

Magnetic filter operation in hydrogen plasmas

Kolev

Lishev

Shivarova

et al. 2007

Plasma Phys. Control. Fusion

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“…Model researches on low pressure ICP discharges have been widely carried out and reported in the literature [9][10][11][12]. Lymberopoulos and Economou [9] reported their fluid model described in details, which includes fluid equations, electron-impact rate coefficients and transport properties, Maxwellf's equations as well as computational scheme.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the effect of gas flow in low pressure inductively coupled Ar/N2 plasmas

Tong

2012

Open Physics

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Abstract:The effect of gas flow in low pressure inductively coupled Ar/N 2 plasmas operating at the rf frequency of 13.56 MHz and the total gas pressure of 20 mTorr is studied at the gas flows of 5-700 sccm by coupling the plasma simulation with the calculation of flow dynamics. The gas temperature is 300 K and input power is 300 W. The Ar fractions are varied from 0% to 95%. The species taken into account include electrons, Ar atoms and their excited levels, N 2 molecules and their seven different excited levels, N atoms, and Ar + , N + , N 2 + , N 4 + ions. 51 chemical reactions are considered. It is found that the electron densities increase and electron temperatures decrease with a rise in gas flow rate for the different Ar fractions. The densities of all the plasma species for the different Ar fractions and gas flow rates are obtained. The collisional power losses in plasma discharges are presented and the effect of gas flow is investigated.

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“…Therefore any potential in the kV range will accelerate electrons well above the thermal velocities and this must be taken into account. Therefore, boundary conditions similar to those found in [Lymberopoulos and Economou, 1995] Once the number densities reach a steady state distribution, the antenna currents and the currents within the sheath region are used to detennine the antenna pattern using a far-field transformation (Fig. 6).…”

Section: A2 Boundary Conditionsmentioning

confidence: 99%

Controlled Precipitation of Radiation Belt Particles

Bell¹

2003

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Two-Dimensional Self-Consistent Radio-Frequency Plasma Simulations Relevant to the Gaseous Electronics Conference Rf Reference Cell

Cited by 137 publications

References 49 publications

Magnetic filter operation in hydrogen plasmas

Magnetic filter operation in hydrogen plasmas

Numerical study of the effect of gas flow in low pressure inductively coupled Ar/N2 plasmas

Controlled Precipitation of Radiation Belt Particles

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