Rotational temperatures and densities of metastable<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>in a multicusp ion source

Bonnie, J. H. M.; Eenshuistra, P. J.; Hopman, H. J.

doi:10.1103/physreva.37.4407

Cited by 5 publications

(9 citation statements)

References 22 publications

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“…Thus, the estimated maximum c 3 Π − u density presented in this study is consistent with the measured value given in Ref. [40].…”

Section: Discussionsupporting

confidence: 92%

“…[9] does not contain a multicusp magnetic field. The density of metastable c 3 Π − u states in a multicusp ion source has been measured earlier to be on the order of 10 10 cm −3 kW −1 [40]. This is approximately two orders of magnitude lower than the upper limit estimated in this study.…”

Section: Discussioncontrasting

confidence: 52%

“…Typically, the most significant de-excitation processes are electron impact de-excitation, collisional quenching with neutral particles and collision to the wall of the plasma chamber, as discussed in Ref. [40]. The radiative lifetime of the c 3 Π − u state depends on the vibrational level and ranges from 1 ms (ν=0) to 10 µs (ν=3) [41].…”

Section: Maximum Production Rate Of Metastable Hydrogen Moleculesmentioning

confidence: 99%

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VUV diagnostics of electron impact processes in low temperature molecular hydrogen plasma

Komppula¹,

Tarvainen²

2015

Plasma Sources Sci. Technol.

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Novel methods for diagnostics of molecular hydrogen plasma processes, such as ionization, production of high vibrational levels, dissociation of molecules via excitation to singlet and triplet states and production of metastable states, are presented for molecular hydrogen plasmas in corona equilibrium. The methods are based on comparison of rate coefficients of plasma processes and optical emission spectroscopy of lowest singlet and triplet transitions, i.e. Lyman-band (B 1 Σ + u → X 1 Σ + g ) and molecular continuum (a 3 Σ + g → b 3 Σ + u ), of the hydrogen molecule in VUV wavelength range. Comparison of rate coefficients of spin-allowed and/or spin-forbidden excitations reduces the uncertainty caused by the non-equilibrium distributions of electron energy and molecular vibrational level, which are typically known poorly in plasma sources. The described methods are applied to estimate the rates of various plasma processes in a filament arc discharge.

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“…Thus, the estimated maximum c 3 Π − u density presented in this study is consistent with the measured value given in Ref. [40].…”

Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 52%

Section: Maximum Production Rate Of Metastable Hydrogen Moleculesmentioning

confidence: 99%

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VUV diagnostics of electron impact processes in low temperature molecular hydrogen plasma

Komppula¹,

Tarvainen²

2015

Plasma Sources Sci. Technol.

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“…In typical hydrogen discharges the majority of metastable states escape from the plasma 25 . Their most significant de-excitation processes are radiative decay induced by collisions and ionization [24][25][26] . Thus, O µ =0 corresponds to minimum photon emission, minimum ionization and maximum chemical potential.…”

Section: Energy Balance Of Laboratory Plasmasmentioning

confidence: 99%

“…O ν =0 . In typical hydrogen discharges the majority of metastable states escape from the plasma 25 . Their most significant de-excitation processes are radiative decay induced by collisions and ionization [24][25][26] .…”

Section: Energy Balance Of Laboratory Plasmasmentioning

confidence: 99%

Plasma heating power dissipation in low temperature hydrogen plasmas

Komppula

Tarvainen

2015

Physics of Plasmas

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Theoretical framework for power dissipation in low temperature plasmas in corona equilibrium is developed. The framework is based on fundamental conservation laws and reaction cross sections and is only weakly sensitive to plasma parameters, e.g. electron temperature and density. The theory is applied to low temperature atomic and molecular hydrogen laboratory plasmas for which the plasma heating power dissipation to photon emission, ionization and chemical potential is calculated. The calculated photon emission is compared to recent experimental results.

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Negative hydrogen ion densities and drift velocities in a multicusp ion source

Eenshuistra

Gochitashvilli

Becker

et al. 1990

Journal of Applied Physics

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We have determined densities of negative hydrogen ions in a discharge by a laser detachment technique. We measured the electron density, the electron temperature, and the positive ion density using a Langmuir probe. We also performed extraction measurements. Combination of H− density measurements and extraction measurements yields information about the H− drift velocity. It was found that the velocity scaled with the square root of the electron temperature. All measurements were done as a function of discharge voltage, discharge current, and gas pressure. The densities are compatible with a semiquantitative model in which H− is produced by dissociative attachment of plasma electrons to vibrationally excited molecules and destroyed by wall collisions at very low pressure and collisions with H atoms, positive ions and/or hot thermal electrons at higher pressure.

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Rotational temperatures and densities of metastableH2in a multicusp ion source

Cited by 5 publications

References 22 publications

VUV diagnostics of electron impact processes in low temperature molecular hydrogen plasma

VUV diagnostics of electron impact processes in low temperature molecular hydrogen plasma

Plasma heating power dissipation in low temperature hydrogen plasmas

Negative hydrogen ion densities and drift velocities in a multicusp ion source

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