Study of a New Plasma Source for Free-Standing Plasmas

Schweitzer, U.; Schulz, Andreas; Walker, M.; Schumacher, U.; Stroth, U.; Baumgärtner, K.‐M.

doi:10.1002/ppap.200732311

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…In all calculations, the ion sheath was assumed to be collisionless. An effective electron temperature was also determined from the current in the transition region of the I-V characteristics using [35]:…”

Section: Methodsmentioning

confidence: 99%

Spectroscopic diagnostics of low-pressure inductively coupled Kr plasma using a collisional–radiative model with fully relativistic cross sections

Gangwar

Dipti

Srivastava

et al. 2016

Plasma Sources Sci. Technol.

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A collisional-radiative (C-R) model for krypton plasma using fully relativistic distortedwave cross sections for electron excitations was developed. The model was applied to the characterization of inductively coupled Kr plasma with cylindrical geometry over the pressure regime 1-50 mTorr. Radially averaged emission intensities from transitions of Kr (4p 5 5p → 4p 5 5s) in the range 500-900 nm were recorded at 17 cm from the planar RF-driven coil, with the plasma operated in the inductive regime (H mode). The measured emission intensities were then fitted by varying the electron density, n e , and electron temperature, T e , in the C-R model. At both low and high pressures, variations of the electron density by over two orders of magnitude had only a minor role on the relative emission intensities. On the other hand, T e values deduced from the comparison between experiment and model decreased from 6.7 to 2.6 eV as pressure increased from 1 to 50 mTorr. These results are found to be in good agreement with the effective electron temperature determined from Langmuir probe measurements and the predictions of a model based on the particle balance equation of charged particles.

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Section: Methodsmentioning

confidence: 99%

Spectroscopic diagnostics of low-pressure inductively coupled Kr plasma using a collisional–radiative model with fully relativistic cross sections

Gangwar

Dipti

Srivastava

et al. 2016

Plasma Sources Sci. Technol.

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“…To address this issue, a new type of plasma source, the Microwave Concentrator has been developed and first results can be found in [1], [2], [3]. It is an extension of the ellipsoidal plasma reactor proposed by Füner et al [4] which is successfully used for diamond film deposition.…”

Section: Introductionmentioning

confidence: 98%

“…During plasma operation, the electron density correlates with the electric field distribution. For this reason, this geometry proved to be unsatisfactory since it is not suitable for generation of a homogeneous plasma [2]. To overcome this problem, an improved geometry, the Microwave Concentrator Stack (MCS), was developed and will be presented in this paper.…”

Section: Introductionmentioning

confidence: 98%

The Microwave Concentrator Stack: A Source for Free‐Standing, Linearly Extended Plasmas

Schweitzer¹,

Schulz²,

Walker³

et al. 2007

Contrib. Plasma Phys.

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A new type of plasma source, the Microwave Concentrator Stack, presented in this paper is a device of a geometry that can be described as an elliptical cylinder with additional metallic structures for shaping the electric field in its inside. The basic idea is to concentrate the electric field strength of microwaves on one of its focal lines by coupling microwave power into it on the other focal line. Even though the dimensions of the Concentrator Stack are too small compared to the wavelength of the microwaves to assume wave-optics behavior, a pronounced maximum of the electric field intensity is created on the focal line.By placing an evacuated glass tube around the focal line, free-standing plasmas can be generated by the strong electric field. In the low pressure range (10 to 200 Pa), the plasma displays very good one-dimensional homogeneity along the focal line of the Concentrator Stack. At higher pressures the plasma contracts to several ball-shaped discharges, whose positions correspond to the aforementioned metallic structures inside the Concentrator Stack.The electric field distribution was calculated and optimized for various versions of the Concentrator Stack using the finite element software Comsol Multiphysics TM and also measured with PET absorber sheets. Measurements and calculations are in excellent agreement.

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