Low frequency oscillations of an H- ion rich reflex discharge

Baribaud, M.; Monte, J.; Zadworny, F.

doi:10.1016/0375-9601(71)90519-6

Cited by 2 publications

(11 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All measurements are in excellent agreement, except for those by Coplan & Ogilvie (1970), who seemed to overestimate their results by a factor 2-4, and Koopman (1968), who underestimate them by about one order of magnitude. Finally, Baribaud et al (1971) and Baribaud (1972) reported a value of σ 10 = (14 ± 8) × 10 −20 m 2 at 5 keV, in good agreement with the other measurements. It is interesting to remark that the additive rule estimates using data in H 2 (Gealy & van Zyl 1987a) and O (Van Zyl & Stephen 2014) are 30% lower on average than the direct measurements in H 2 O.…”

Section: H + -H 2 Osupporting

confidence: 87%

“…A polynomial fit of degree 4 in log 10 on the reconstructed (H − , H 2 O) two-electron-loss cross section. At 5 keV, the additive rule fit is within 5% of the reported value for H 2 O (Baribaud et al 1971). Validity range i = 650-7600 km s −1 (2.2-300 keV).…”

Section: H − -H 2 Osupporting

confidence: 79%

“…• Reaction σ 01 (H 0 → H + ) Measurements. Dagnac et al (1969Dagnac et al ( , 1970) measured oneelectron-loss cross sections for the hydrogen impact on H 2 O between 1.5 and 60 keV, which are in excellent agreement in their common range with the newer values given by Luna et al (2007) in the 15 − 90 keV range, which include both reaction channels H → H + + H 2 O + + 2e and → H + + H 2 O + e. Baribaud et al (1971) and Baribaud (1972) reported a value of σ 01 = (1.6 ± 0.8) × 10 −20 m 2 at 5 keV in good agreement. Gobet et al (2006) reported cross sections between 20 and 150 keV, whereas Toburen et al (1968) made measurements between 100 keV and 2500 keV, all in excellent agreement.…”

Section: H 0 -H 2 Omentioning

confidence: 65%

“…We therefore supplemented our data at low energy with an adjustment of the Koopman (1968) measurement at 73 eV u −1 (118 km s −1 ) by multiplying by a calibrating factor of 7.15 (σ adj 10 ≈ 9 × 10 −20 m 2 ), and placing less weight on this particular dataset because of the large uncertainties. We note that the additive rule using the results of Rudd et al (1985c) Impactor speed [km s -1 ] Baribaud et al (1971) AR H 2 +O -10 Baribaud et al (1971) AR H 2 +O, scaled…”

Section: (Middle)mentioning

confidence: 99%

“…• Reaction σ −10 (H − → H 0 ) Measurements. The only measurement found for the oneelectron loss by H − in H 2 O is that of Baribaud et al (1971;also in Baribaud 1972), who reported a unique value at 5 keV in H 2 O, σ −10 = 7.5 × 10 −20 m 2 . Uncertainty.…”

Section: H − -H 2 Omentioning

confidence: 99%

See 4 more Smart Citations

Solar wind charge exchange in cometary atmospheres

Wedlund

Bodewits

Alho

et al. 2019

A&A

View full text Add to dashboard Cite

Context. Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet, mass-loading the solar wind through an effective conversion of fast light solar wind ions into slow heavy cometary ions. Aims. To understand these processes and place them in the context of a solar wind plasma interacting with a neutral atmosphere, numerical or analytical models are necessary. Inputs of these models, such as collision cross sections and chemistry, are crucial. Methods. Book-keeping and fitting of experimentally measured charge-changing and ionization cross sections of hydrogen and helium particles in a water gas are discussed, with emphasis on the low-energy/low-velocity range that is characteristic of solar wind bulk speeds (<20 keV u−1/2000 km s−1). Results. We provide polynomial fits for cross sections of charge-changing and ionization reactions, and list the experimental needs for future studies. To take into account the energy distribution of the solar wind, we calculated Maxwellian-averaged cross sections and fitted them with bivariate polynomials for solar wind temperatures ranging from 105 to 106 K (12–130 eV). Conclusions. Single- and double-electron captures by He2+ dominate at typical solar wind speeds. Correspondingly, single-electron capture by H+ and single-electron loss by H− dominate at these speeds, resulting in the production of energetic neutral atoms (ENAs). Ionization cross sections all peak at energies above 20 keV and are expected to play a moderate role in the total ion production. However, the effect of solar wind Maxwellian temperatures is found to be maximum for cross sections peaking at higher energies, suggesting that local heating at shock structures in cometary and planetary environments may favor processes previously thought to be negligible. This study is the first part in a series of three on charge exchange and ionization processes at comets, with a specific application to comet 67P/Churyumov-Gerasimenko and the Rosetta mission.

show abstract

Section: H + -H 2 Osupporting

confidence: 87%

Section: H − -H 2 Osupporting

confidence: 79%

Section: H 0 -H 2 Omentioning

confidence: 65%

Section: (Middle)mentioning

confidence: 99%

Section: H − -H 2 Omentioning

confidence: 99%

See 3 more Smart Citations

Solar wind charge exchange in cometary atmospheres

Wedlund

Bodewits

Alho

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

Solar wind charge exchange in cometary atmospheres. I. Charge-changing and ionization cross sections for He and H particles in H$_2$O

Wedlund,

Bodewits,

Alho

et al. 2019

Preprint

View full text Add to dashboard Cite

Context. Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet, mass-loading the solar wind through an effective conversion of fast light solar wind ions into slow heavy cometary ions. Aims. To understand these processes and place them in the context of a solar wind plasma interacting with a neutral atmosphere, numerical or analytical models are necessary. Inputs of these models, such as collision cross sections and chemistry, are crucial. Methods. Book-keeping and fitting of experimentally measured charge-changing and ionization cross sections of hydrogen and helium particles in a water gas are discussed, with emphasis on the low-energy/low-velocity range that is characteristic of solar wind bulk speeds (< 20 keV u −1 /2000 km s −1 ). Results. We provide polynomial fits for cross sections of charge-changing and ionization reactions, and list the experimental needs for future studies. To take into account the energy distribution of the solar wind, we calculated Maxwellian-averaged cross sections and fitted them with bivariate polynomials for solar wind temperatures ranging from 10 5 to 10 6 K (12 − 130 eV). Conclusions. Single-and double-electron captures by He 2+ dominate at typical solar wind speeds. Correspondingly, single-electron capture by H + and single-electron loss by H − dominate at these speeds, resulting in the production of energetic neutral atoms (ENAs). Ionization cross sections all peak at energies above 20 keV and are expected to play a moderate role in the total ion production. However, the effect of solar wind Maxwellian temperatures is found to be maximum for cross sections peaking at higher energies, suggesting that local heating at shock structures in cometary and planetary environments may favor processes previously thought to be negligible. This study is the first part in a series of three on charge exchange and ionization processes at comets, with a specific application to comet 67P/Churyumov-Gerasimenko and the Rosetta mission.

show abstract

Low frequency oscillations of an H- ion rich reflex discharge

Cited by 2 publications

References 1 publication

Solar wind charge exchange in cometary atmospheres

Solar wind charge exchange in cometary atmospheres

Solar wind charge exchange in cometary atmospheres. I. Charge-changing and ionization cross sections for He and H particles in H$_2$O

Contact Info

Product

Resources

About