Velocity distribution function of ion swarm in a weakly ionised gas in a constant mean free time encounter region

Makabe, Toshiaki; Misawa, Kentaro; Mori, T.

doi:10.1088/0022-3727/14/2/012

Cited by 18 publications

(2 citation statements)

References 23 publications

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“…Those theories did not consider the different average kinetic energies parallel and perpendicular to the electrostatic field used and/or they did not incorporate skewness, kurtosis, or correlation in the three-dimensional ion velocity distribution function. Such effects were considered by Makabe et al (1981), but only in the case where the interaction between the ion and reactive neutral was due entirely to the ion-induced dipole interaction; in addition, they used the BGK approximation to the Boltzmann equation. The errors in all these theories are in addition to other possible measurement errors pointed out by McDaniel (1970).…”

Section: Introductionmentioning

confidence: 99%

Cross Sections and Rate Coefficients for O⁺ Reacting With N₂, O₂, and NO

Viehland

Johnsen

2019

JGR Atmospheres

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Ion‐molecule reaction cross sections between 0.03 and 3 eV can best be inferred from data taken in drift tube mass spectrometers. For the title reactions, the cross sections inferred from drift‐tube measurements in the late 1970s have been accepted as accurate, even though the methods used to infer them made substantial assumptions about the ion velocity distribution functions. Here the Gram‐Charlier method for solving the Boltzmann equation is used to obtain ion distribution functions that are anisotropic, having different average energies parallel and perpendicular to the uniform electrostatic field. The Gram‐Charlier method incorporates skewness, kurtosis, and correlation between the motions parallel and perpendicular to the field. This leads to more accurate ion distribution functions from which more accurate reaction cross sections have been inferred. The results differ by as much as 50% from the generally accepted cross sections that are currently used to model ion‐neutral reactions in the upper atmosphere.

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Section: Introductionmentioning

confidence: 99%

Cross Sections and Rate Coefficients for O⁺ Reacting With N₂, O₂, and NO

Viehland

Johnsen

2019

JGR Atmospheres

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“…Velocity distributions of Na+ ions in helium at the E/n indicated. The full curves represent the experimental results and the broken and dotted curves the corresponding results calculated from the analytic expressions ofMakabe et al (1981) andWhealton and Woo (1972), respectively. Ce,,,, and CW are the RMS velocities determined from the experimental curve and Wannier's equation, respectively.…”

mentioning

confidence: 99%

Velocity distribution functions of Na⁺ions drifting in helium, neon and argon

Hogan

Ong

1988

J. Phys. B: At. Mol. Opt. Phys.

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Measurements are reported of the velocity distribution functions of roomtemperature Na+ ions drifting in helium, neon and argon gas under the influence of an electric field at E/n in the range 16-261 Td. The distributions were found to become wider, have larger RMS velocities and become more skewed toward higher velocities as E / n was increased. They also were shifted increasingly further from the velocity space origin with increasing E/n. The ion-to-neutral-mass ratio was found to be an important parameter in determining the properties of the distributions. The experimental results were used to evaluate the accuracy of theoretical analytic expressions for the velocity distributions.

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