Modeling of hydrogen ground state rotational and vibrational temperatures in kinetic plasmas

Farley, D. R.; Stotler, D.P.; Lundberg, D.P.; Cohen, Samuel A.

doi:10.1016/j.jqsrt.2010.10.015

Cited by 20 publications

(28 citation statements)

References 56 publications

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“…It is typically the most intense emission of the hydrogen molecule in low pressure plasmas why it is often utilized for diagnostics concerning the rotational or vibrational population. Details of the Fulcher-α transition and the properties of the involved electronic states have been described extensively multiple times (see for example [17,14]), therefore only the most important facts are given in the following. The upper electronic state is split into the d 3 Π + u and d 3 Π − u states because of λ-doubling.…”

Section: The Fulcher-α Transition Of Molecular Hydrogenmentioning

confidence: 99%

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Briefi

Rauner

Fantz

2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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Vibrational and rotational excitation of the hydrogen molecule can significantly effect molecular reaction rates in low pressure low temperature plasmas, for example for the creation of H − /D − ions via the dissociative attachment process. In general, the rotational population in these discharges is known to be non-thermal with an overpopulation of states with high rotational quantum number N. In contrast to a sophisticated direct measurement of the rotational distribution in the X 1 Σ + g , v = 0 state, it is demonstrated that the determination can also be carried out up to high-N levels rather easily via optical emission spectroscopy utilizing the Fulcher-α transition of H 2 and D 2. The measured rotational populations can be described with a two-temperature distribution where the cold part reflects the population according to the gas temperature of the discharge. This has been verified by using the emission of the second positive system of nitrogen as independent gas temperature diagnostic. The hot part where the rotational temperature reaches several thousand Kelvin arises most probably from recombinative desorption of hydrogen at the discharge vessel wall where parts of the binding energy are converted into rotational excitation. Neglecting the hot population-what is often done when using the Fulcher-α transition as gas temperature diagnostic-can lead to a strong overestimation of T gas. No fundamental differences in the rotational distributions between hydrogen and deuterium have been found, only the hot rotational temperature is smaller for D 2 indicating an isotope-dependency of the recombinative desorption process.

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Section: The Fulcher-α Transition Of Molecular Hydrogenmentioning

confidence: 99%

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Briefi

Rauner

Fantz

2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…The dominant loss channel is spontaneous radiative decay. It has been proven that a corona model describes the equilibrium population of the P d u 3 correctly, as contributions from other population channels like cascades from higher lying levels can be neglected [27]. Finally, knowing both the rotational and vibrational distributions of the P d u 3 state, the integrated emissivity of the Fulcher-α transition can be calculated.…”

Section: Determining Plasma Parameters From Oesmentioning

confidence: 99%

Experimental benchmark of the NINJA code for application to the Linac4 H⁻ion source plasma

et al. 2017

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“…An OES spectrum was acquired at 20 horizontal positions between the two electrodes to study the spatial relative intensities of critical species . The wavelengths of these species have been interpreted as in the literature . An average of 10 frames with 100 ms exposure time was recorded in the wavelength range 300 to 933 nm.…”

Section: Methodsmentioning

confidence: 99%

Roll‐to‐Roll Production of Graphitic Petals on Carbon Fiber Tow

2018

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A scalable roll-to-roll process is employed to produce graphitic petals. A 1-meter sample of graphitic petals on carbon fiber tow is produced with a roll-to-roll radio-frequency plasma chemical vapor deposition method. Microscale characterization reveals increasingly graphitic carbon structures with production time. Correspondingly, macroscale characterization shows enhanced functional performance with production time: decreasing electrical resistance and increasing capacitance. Using optical emission spectroscopy, important species in the plasma are studied and used to determine the plasma gas temperature. The results demonstrate that 1) successful cost-driven production of graphitic petals is possible, 2) a plasma diagnostic technique is capable of real-time process monitoring, and 3) meaningful material characterization methods are amenable to a production setting. Finally, valuable experiential learnings are shared to inform future equipment design and process development.

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Modeling of hydrogen ground state rotational and vibrational temperatures in kinetic plasmas

Cited by 20 publications

References 56 publications

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Experimental benchmark of the NINJA code for application to the Linac4 H⁻ion source plasma

Roll‐to‐Roll Production of Graphitic Petals on Carbon Fiber Tow

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Modeling of hydrogen ground state rotational and vibrational temperatures in kinetic plasmas

Cited by 20 publications

References 56 publications

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

Experimental benchmark of the NINJA code for application to the Linac4 H−ion source plasma

Roll‐to‐Roll Production of Graphitic Petals on Carbon Fiber Tow

Contact Info

Product

Resources

About

Experimental benchmark of the NINJA code for application to the Linac4 H⁻ion source plasma