On the differences between ionizing helium and argon plasmas at atmospheric pressure

Jonkers, J Jeroen; Sande, Marco van de; Sola, A; Gamero, A; Mullen, Joost van der

doi:10.1088/0963-0252/12/1/304

Cited by 74 publications

(83 citation statements)

References 26 publications

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“…Since n e values are for r = 0, we divided the value by 1.64 assuming a Bessel-like profile. For the value of C, we used R * = 3 mm, λ h = 0.0178 W(mK) −1 [26] and S heat = 6.7×10 −19 m 3 s −1 based on the work of references [27][28][29]. It can be seen that the agreement between theory and experiment is reasonable and falls in between the error bars.…”

Section: Discussionmentioning

confidence: 99%

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Hübner

Iordanova

Palomares

et al. 2012

Eur. Phys. J. Appl. Phys.

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Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. Abstract. The axial dependency of the central-axis value of the heavy particle density and temperature of surface-wave plasmas is studied using Rayleigh scattering (RyS). The plasma is generated at a frequency of 2.45 GHz in argon by a surfatron operating under the standard settings of a power of 45 W, a flow rate of 50 sccm and a pressure of 20 mbar. To investigate the effect of the pressure on the gas temperature, we also investigated 6 and 10 mbar plasmas. By using a two-dimensional intensified CCD array we could determine and eliminate the influence of false stray light, a major disturbing factor in the determination of the Rayleigh signal. In order to trace the energy fluxes that determine the gas temperature, we performed Thomson scattering so that the properties of the electron gas are known. It is found that the gas temperature, T a, depends on the wall temperature and the product of the gas pressure and the electron pressure. The latter implies that Ta follows the electron density axially, meaning that it is highest at the launcher and decreases monotonically in the wave propagation direction. The maximum gas temperature of around Ta = 800 K is found close to the launcher for the highest gas pressure of 20 mbar. For lower pressures we find lower Ta values. The extrapolation of Ta toward the end of the plasma column leads to a temperature of about 320 K. This study reveals that, for the argon plasmas under study, the central-axis values of the gas temperature are determined by the balance between the heating of the gas by means of elastic electron collisions and the cooling due to heat conduction from the center to the wall.

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Section: Discussionmentioning

confidence: 99%

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Hübner

Iordanova

Palomares

et al. 2012

Eur. Phys. J. Appl. Phys.

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“…In contrast to n e and T g obtained experimentally, the densities of ions (Ar + and Ar 2 + ) and excited states (Ar(4s) and Ar(4p)) are determined by solving the charge neutrality equation and the balance equations for Ar 2 + , Ar(4s) and Ar(4p) while T e stems from the balance equation of electrons [37,46] …”

Section: Balance Equations For the Modelmentioning

confidence: 99%

Absorption spectroscopy measurements of resonant and metastable atom densities in atmospheric-pressure discharges using a low-pressure lamp as a spectral-line source and comparison with a collisional-radiative model

Castaños-Martínez

Moisan

2010

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…The electron-neutral collision frequency, ν m , in Equations 26 and 27 is a function of the neutral density and electron temperature. ν m is calculated using the equations given by Jonkers et al 30 In the model, the neutral density, N, is evaluated by:…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical investigation of the electric field distribution and the power deposition in the resonant cavity of a microwave electrothermal thruster

Yildiz

Çelik

2017

AIP Advances

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Microwave electrothermal thruster (MET), an in-space propulsion concept, uses an electromagnetic resonant cavity as a heating chamber. In a MET system, electromagnetic energy is converted to thermal energy via a free floating plasma inside a resonant cavity. To optimize the power deposition inside the cavity, the factors that affect the electric field distribution and the resonance conditions must be accounted for. For MET thrusters, the length of the cavity, the dielectric plate that separates the plasma zone from the antenna, the antenna length and the formation of a free floating plasma have direct effects on the electromagnetic wave transmission and thus the power deposition. MET systems can be tuned by adjusting the lengths of the cavity or the antenna. This study presents the results of a 2-D axis symmetric model for the investigation of the effects of cavity length, antenna length, separation plate thickness, as well as the presence of free floating plasma on the power absorption. Specifically, electric field distribution inside the resonant cavity is calculated for a prototype MET system developed at the Bogazici University Space Technologies Laboratory. Simulations are conducted for a cavity fed with a constant power input of 1 kW at 2.45 GHz using COMSOL Multiphysics commercial software. Calculations are performed for maximum plasma electron densities ranging from 1019 to 1021 #/m3. It is determined that the optimum antenna length changes with changing plasma density. The calculations show that over 95% of the delivered power can be deposited to the plasma when the system is tuned by adjusting the cavity length.

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On the differences between ionizing helium and argon plasmas at atmospheric pressure

Cited by 74 publications

References 26 publications

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Rayleigh scattering on a microwave surfatron plasma to obtain axial profiles of the atom density and temperature

Absorption spectroscopy measurements of resonant and metastable atom densities in atmospheric-pressure discharges using a low-pressure lamp as a spectral-line source and comparison with a collisional-radiative model

Numerical investigation of the electric field distribution and the power deposition in the resonant cavity of a microwave electrothermal thruster

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