H+<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and H+<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>collisions: Experimental charge-production cross se

Zyl, B. Van; Neumann, H; Le, T.Q.; Amme, Robert C.

doi:10.1103/physreva.18.506

Cited by 26 publications

(21 citation statements)

References 19 publications

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“…Therefore, for the given incident¯ux the magnetic mirroring eect alone cannot generate a signi®cant red shift in the magnetic-zenith pro®le. The same conclusion is valid for r a emission whose related cross sections can be obtained from Van Zyl and Neumann (1980) and Yousif et al (1986). Moreover, variation of the characteristic energy i 0 of the incident ux has very little eect on the red shift.…”

Section: In¯uence Of Magnetic Mirroring On the R B Doppler Pro®le In supporting

confidence: 72%

“…If is a proton, the collision is a capture. The r b emission cross sections for x 2 and y 2 are taken from Van Zyl and Neumann (1980) from 30 eV to 3 keV and from Shen (1993) for higher energies. As far as we know, there is no measurement of the cross sections for collisions with atomic oxygen: the r b emission cross sections associated with y have been obtained by dividing the y 2 cross sections by a factor of two.…”

Section: In¯uence Of Magnetic Mirroring On the R B Doppler Pro®le In mentioning

confidence: 99%

“…This value has been estimated from the few dierential cross section data which are available to date (Fleischmann et al, 1967(Fleischmann et al, , 1974Cisneros et al, 1976;Van Zyl et al, 1978;Newman et al, 1986;Johnson et al, 1988;Gao et al, 1990).…”

Section: Collisional Angular Redistributionmentioning

confidence: 99%

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Proton transport model in the ionosphere. 2. Influence of magnetic mirroring and collisions on the angular redistribution in a proton beam

Galand

Lilensten²,

Kofman³

et al. 1998

Ann Geophysicae

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Abstract. We investigate the in¯uence of magnetic mirroring and elastic and inelastic scattering on the angular redistribution in a proton/hydrogen beam by using a transport code in comparison with observations. H-emission Doppler pro®les viewed in the magnetic zenith exhibit a red-shifted component which is indicative of upward¯uxes. In order to determine the origin of this red shift, we evaluate the in¯uence of two angular redistribution sources which are included in our proton/ hydrogen transport model. Even though it generates an upward¯ux, the redistribution due to magnetic mirroring eect is not sucient to explain the red shift. On the other hand, the collisional angular scattering induces a much more signi®cant red shift in the lower atmosphere. The red shift due to collisions is produced by`1 -keV protons and is so small as to require an instrumental bandwidth`0X2 nm. This explains the absence of measured upward proton/hydrogen¯uxes in the Proton I rocket data because no useable data concerning protons`1 keV are available. At the same time, our model agrees with measured ground-based H-emission Doppler pro®les and suggests that previously reported red shift observations were due mostly to instrumental bandwidth broadening of the pro®le. Our results suggest that Doppler pro®le measurements with higher spectral resolution may enable us to quantify better the angular scattering in proton aurora.

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Section: In¯uence Of Magnetic Mirroring On the R B Doppler Pro®le In supporting

confidence: 72%

Section: In¯uence Of Magnetic Mirroring On the R B Doppler Pro®le In mentioning

confidence: 99%

See 1 more Smart Citation

Proton transport model in the ionosphere. 2. Influence of magnetic mirroring and collisions on the angular redistribution in a proton beam

Galand

Lilensten²,

Kofman³

et al. 1998

Ann Geophysicae

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“…The algorithm was successfully validated in Kozelov (1994) by comparison with particle data from a rocket campaign by Søraas (1974). The algorithm takes into account the 3-component atmosphere (N 2 , O, O 2 ) (Hedin, 1987), the influence of the Earth's dipolar magnetic field (Kozelov, 1993) and the collisional angle scattering based on differential cross sections evaluated from laboratory measurements (Fleischmann et al, 1967(Fleischmann et al, , 1974Newman et al, 1986; Van Zyl et al, 1978;Gao et al, 1990). The formalism of the calculation of the Doppler profiles from transport algorithms is well-known; see, for example, Lorentzen et al (1998).…”

Section: Estimation Of Proton Energymentioning

confidence: 99%

Variations of auroral hydrogen emission near substorm onset

et al. 2005

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Abstract. The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the average energy of precipitating protons and the emission intensity of the hydrogen Balmer line. Two different populations of precipitating protons were observed during an auroral substorm. The first of these is associated with a diffuse hydrogen emission that is usually observed in the evening sector of the auroral oval and located equatorward of the discrete electron arcs associated with substorm onset. The average energy of the protons during this precipitation was ∼20-35 keV, and the energy flux was ∼3×10 −4 Joule/m 2 s. The second proton population was observed 1-2 min after the breakup during 4-5 min of the expansion phase of substorm into the zone of bright, discrete auroral structures (N-S arcs). The average energy of the protons in this population was ∼60 keV, and the energy flux was ∼2.2×10 −3 Joule/m 2 s. The observed spatial structure of hydrogen emission is additional evidence of the higher energy of precipitated protons in the second population, relative to the protons in the diffuse aurora. We believe that the most probable mechanism of precipitation of the second population protons was pitch-angle scattering of particles due to non-adiabatic motion in the region of local dipolarization near the equatorial plane.

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“…The input models used are also expected to give an oversimplified picture about the real precipitation process, which in reality includes many neutral atmospheric components and more structured neutral profiles and cross-section profiles than adopted in the study. For example, although in some collision processes an elastic DSCS has been found to provide a good approximation for an inelastic process as well [see Van Zyl et al, 1978], in our work the same scattering distribution function was adopted in models M1-M3 and in models M4-M6 for simplicity. Moreover, precipitating hydrogen atoms can change to H + ions, and in inelastic processes, part of the energy heats the electrons.…”

Section: Can Approximate E/•t M (E '[T(x)) Such Approximation Ismentioning

confidence: 99%