Polarization of Lyman-β radiation from atomic hydrogen excited by electron impact from near-threshold energy to 1000 eV

James, G. K.; Dziczek, D.; Slevin, J; Bray, Igor

doi:10.1103/physreva.66.042710

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…Around several hundred eV the polarization tends to zero (at around 150 eV in the Lyman alpha case) and to a negative asymptote at high energies. In the decreasing part of the curve, the results are similar with the Bethe theory [ James et al , 1998, 2002; Merabet et al , 1999] (Figures 2 and 3) .…”

Section: Description Of the Polarizing Mechanismssupporting

confidence: 81%

“…Therefore it is necessary to proceed to laboratory measurements. Some have been made on the Lyman alpha and beta lines for atomic hydrogen for energies ranging from the threshold to 1000 eV [ James et al , 1998, 2002] and for the helium 1 snp series [ Merabet et al , 1999]. In each case, the curve of the polarization rate shows similar profiles (Figure 1).…”

Section: Description Of the Polarizing Mechanismsmentioning

confidence: 99%

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Considering the polarization of the oxygen thermospheric red line for space weather studies

et al. 2006

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International audienceSpace weather thermospheric monitoring requires real-time and large-scale measurements. In order to monitor the thermospheric variations due to geomagnetic activity, one relies mostly on the measurements of the intensity of the atomic oxygen green line and on the indirect measurement of the total electron content. These two parameters do not allow retrieving the full characteristics of the thermosphere, and a third proxy is required, for example, in orbitography. We propose to use the polarization of the atomic oxygen red line to fulfill this requirement. The first measurements of the polarization of thermospheric nightglow lines have been performed in the first part of the twentieth century and especially during the last International Geophysical Year. Amongst the oxygen visible lines, only the red one seems to be potentially polarized. However, there exists a disagreement between the different measurements. At the origin of the polarization, there is always a dissymmetric mechanism. It triggers either an emission process, a light scattering, or, in the case of the oxygen red line, a collision mechanism. This paper reviews the different experiments performed in the past and proposes to explore this matter with modern facilities. If successful, this investigation could lead to a systematic reanalysis of the previous red line interferometric measurements

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Section: Description Of the Polarizing Mechanismssupporting

confidence: 81%

Section: Description Of the Polarizing Mechanismsmentioning

confidence: 99%

Considering the polarization of the oxygen thermospheric red line for space weather studies

et al. 2006

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“…Scattering experiments to measure polarization, orientation and alignment were first carried out in the late 1960s and the experimental and theoretical developments have been described in detail in the book by Andersen and Bartschat [3]. Polarization of Ly α and Ly β radiation from hydrogen excited by electron impact has recently been measured by James et al [4,5] for incident electron energies up to 1800 eV and 1000 eV respectively and excellent agreement with close-coupling theory obtained.…”

Section: Introductionmentioning

confidence: 81%

The theory of polarization of radiation emitted by excited atoms

Peach¹,

Feautrier²,

Saraph³

2009

J. Phys. A: Math. Theor.

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The polarization of radiation emitted in spectral lines provides an important diagnostic tool when the relationship between the mechanisms that excite the atomic or molecular energy levels and the polarization is understood. The gas is assumed to be in statistical equilibrium and we present a general formulation of the theory in which all collisional and radiative excitation and decay processes are included. The colliding particles are assumed to have an anisotropic velocity distribution with cylindrical symmetry and the theory allows for rotation of the axis of observation. Some assumptions made in previous work are removed by the introduction of a completely quantum-mechanical description of the collision processes. Such a theory is important both for the detailed analysis of collision experiments in the laboratory and for the analysis of spectra emitted by astrophysical plasmas.

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Angular and polarization properties of the Lyman- α1 line 2p3/2→1s1/2<

Tian

et al. 2022

Phys. Rev. A

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Polarization of Lyman-β radiation from atomic hydrogen excited by electron impact from near-threshold energy to 1000 eV

Cited by 5 publications

References 20 publications

Considering the polarization of the oxygen thermospheric red line for space weather studies

Considering the polarization of the oxygen thermospheric red line for space weather studies

The theory of polarization of radiation emitted by excited atoms

Angular and polarization properties of the Lyman- α1 line 2p3/2→1s1/2<

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