Spectroscopic arcjet diagnostic under thermal equilibrium and nonequilibrium conditions

Zube, Dieter M.; Auweter‐Kurtz, Monika

doi:10.2514/6.1993-1792

Cited by 8 publications

(4 citation statements)

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“…For a gas temperature of 1400 K, slightly greater than that of the anode wall, T es /Tg ; 2 (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). This value for the gas temperature is reasonable because nozzle surface temperature measurements yield T noz ; 950 K and the numerical model predicts T gas ; 1200 K along the anode wall.…”

Section: E Electron Temperaturementioning

confidence: 87%

“…19 Additional investigations of plasma conditions inside the nozzle and constrictor have been performed on low-and mediumpower arcjets. 20,21 Other internal diagnostic works have included internal emission spectroscopy measurements in the nozzle expansion region of a 26-kW ammonia arcjet. 22 Curran et al 23 studied arc energy deposition in the segmented anode of a 1-to 2-kW arcjet, the distribution of the arc attachment, and its effects on the performance characteristics of the device.…”

Section: Introductionmentioning

confidence: 99%

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Arcjet Anode Plasma Measurements Using Electrostatic Probes

Tiliakos

Burton

Krier

1998

Journal of Propulsion and Power

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A 1-kW hydrazine arcjet thruster has been modi ed for internal probing of the anode sheath boundary layer with an array of 14 electrostatic microprobes ush mounted into the anode body. Axial and azimuthal distributions of the plasma properties oating potential, anode sheath potential, wall current density, electron number density, and electron temperature have been obtained for arc currents between 7.8 and 10.6 A and propellant ow rates of 40-60 mg/s. The speci c power ranged from 18.8 to 27.4 MJ/ kg. Azimuthal symmetry has been veri ed for all arcjet operating conditions. The electron temperature data show that the near-anode plasma is highly nonequilibrium. Most of the current density and anode heating is located within 2 -4 mm of the constrictor exit, with the location affected more by mass ow rate than by arc current. The axial anode heating distribution is closely coupled to current density and accounts for ;18-24% of the total input power. Reasonable agreement between a numerical model and experimental results is found for a constant value of the electron inelastic energy-loss factor. NomenclatureA eff = effective probe collection area, m 2 A p = geometric probe collection area, m 2 E = near-anode electric eld, V/mm E pl = electric eld in bulk plasma, V/mm e = electronic charge, C I = applied current to arcjet, A I e-sat = electron saturation current, mA I p = total probe current, mA j = current density, A/cm 2 j a = anode current density, A /cm 2 j th = thermal current density, A/cm 2 k = Boltzmann constant, J/K L = nozzle axial length, mm M i = reduced N 1 and H 1 mass, kg m Ç = propellant mass ow rate, mg /s m e = electron mass, kg n es = electron number density, m 2 3 n r = number density of species r, m 2 3 q e = anode heating by electrons, W/cm 2 r p = probe radius, mm T = temperature, K V = voltage, V W = anode tungsten material work function, eV a = degree of ionization « i = ionization potential, eV lD = Debye length, mm lrs = mean free path, mm l s = sheath thickness, mm f = potential, V

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Section: E Electron Temperaturementioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Arcjet Anode Plasma Measurements Using Electrostatic Probes

Tiliakos

Burton

Krier

1998

Journal of Propulsion and Power

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“…If the LTE condition was valid in RF-generated plasma, the collision between free electrons and argon species reached equilibrium and the excitation temperature equaled the electron temperature. But under non-LTE conditions, the excitation temperature measured should be called the apparent excitation temperature [23] . The apparent excitation temperature was concerned with not only the electron temperature but also the electron density.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…[21]. On the other hand, ZUBE [23] calculated the electron temperature based on the apparent excitation temperature and electron density in the non-LTE hydrogen plasma. This resulted in a new method for plasma spectroscopy.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Diagnostics of Parameters by Optical Emission Spectroscopy and Langmuir Probe in Mixtures (SiH₄/C₂H₄/Ar) Radio-Frequency Discharge

吴静.张鹏云

2011

Plasma Sci. Technol.

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Optical emission spectroscopy and Langmuir Probe diagnostics were incorporated into the experiment, in which dust particles were formed in-situ by using reactive mixture gases (SiH4/C2H4/Ar) in a radio-frequency (RF) discharge plasma. The excitation temperature was first calculated by combining several optical emission spectra of argon lines and using a Boltzmann distribution to fit the experimental data, then the excitation temperature as functions of both gas pressure and RF power in SiH4/C2H4/Ar discharges for different discharge conditions were obtained. Correspondingly, based on the measurement of the electron temperature by a Langmuir probe, the excitation temperature was compared with the electron temperature, and some discussions were presented. Finally the emission intensities of spectral lines of Si 390.6 nm, Si 2+ 380.6 nm and C + 426.7 nm were measured and presented as functions of pressure, RF power and flow rate of SiH4/C2H4.

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Directions for arcjet technology development

Butler¹,

Cassady²,

King³

1994

25th Plasmadynamics and Lasers Conference

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Spectroscopic arcjet diagnostic under thermal equilibrium and nonequilibrium conditions

Cited by 8 publications

References 1 publication

Arcjet Anode Plasma Measurements Using Electrostatic Probes

Arcjet Anode Plasma Measurements Using Electrostatic Probes

Diagnostics of Parameters by Optical Emission Spectroscopy and Langmuir Probe in Mixtures (SiH₄/C₂H₄/Ar) Radio-Frequency Discharge

Directions for arcjet technology development

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Spectroscopic arcjet diagnostic under thermal equilibrium and nonequilibrium conditions

Cited by 8 publications

References 1 publication

Arcjet Anode Plasma Measurements Using Electrostatic Probes

Arcjet Anode Plasma Measurements Using Electrostatic Probes

Diagnostics of Parameters by Optical Emission Spectroscopy and Langmuir Probe in Mixtures (SiH4/C2H4/Ar) Radio-Frequency Discharge

Directions for arcjet technology development

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Product

Resources

About

Diagnostics of Parameters by Optical Emission Spectroscopy and Langmuir Probe in Mixtures (SiH₄/C₂H₄/Ar) Radio-Frequency Discharge