Mean free paths and elastic and related transport cross sections for neutrals and singly charged ions of Li, Be, and B in hydrogen plasmas

Krstić, Predrag; Schultz, David

doi:10.1063/1.3126549

Cited by 10 publications

(9 citation statements)

References 29 publications

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“…For this purpose the cross-sections from [10] are implemented. A simplified model of "strong-collisions" is applied instead of the full differential cross-sections: the total collision cross-section is taken as 2× diffusion cross-section, and colliding test particles scatter by the angle in the center-of-mass frame.…”

Section: Main Plasma and First Wallmentioning

confidence: 99%

Numerical estimates of the ITER first mirrors degradation due to atomic fluxes

Kotov

Reiter

Kukushkin

et al. 2011

Fusion Engineering and Design

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Section: Main Plasma and First Wallmentioning

confidence: 99%

Numerical estimates of the ITER first mirrors degradation due to atomic fluxes

Kotov

Reiter

Kukushkin

et al. 2011

Fusion Engineering and Design

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“…Thus, it is important to find an analytical expression for the momentum transfer cross-section. At low energies ( 10 4 K), the elastic cross-section can be well approximated by the Massey-Mohr cross section (Krstić & Schultz 2009) σMM = 5 × 10 11 C6 v 2/5 cm 2 .…”

Section: Acknowledgmentsmentioning

confidence: 99%

Magnetic-diffusion-driven shear instability of solar flux tubes

Pandey¹,

Wardle²

2013

Monthly Notices of the Royal Astronomical Society

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The dynamics of the partially ionised solar photosphere and chromosphere can be described by a set of equations that are structurally similar to the magnetohydrodynamic equations, except now the magnetic field is no longer frozen in the fluid but slips through it due to non-ideal magnetohydrodynamic effects which are manifested as Ohm, ambipolar and Hall diffusion. Macroscopic gas motions are widespread throughout the solar atmosphere and shearing motions couple to the non-ideal effects, destabilising low frequency fluctuations in the medium. The origin of this non-ideal magnetohydrodynamic instability lies in the collisional coupling of the neutral particles to the magnetized plasma in the presence of a sheared background flow. Unsurprisingly, the maximum growth rate and most unstable wavenumber depend on the flow gradient and ambient diffusivities.The orientation of the magnetic field, velocity shears and perturbation wave vector play a crucial role in assisting the instability. When the magnetic field and wave vector are both vertical, ambipolar and Ohm diffusion can be combined as Pedersen diffusion and cause only damping; in this case only Hall drift in tandem with shear flow drives the instability. However, for non-vertical fields and oblique wave vectors, both ambipolar diffusion and Hall drift are destabilizing.We investigate the stability of magnetic elements in the network and internetwork regions. The shear scale is not yet observationally determined, but assuming a typical shear flow gradient ∼ 0.1 s −1 we show that the magnetic diffusion shear instability grows on a time scale of one minute. Thus, it is plausible that network-internetwork magnetic elements are subject to this fast growing, diffusive shear instability, which could play an important role in driving low frequency turbulence in the plasma in the solar photosphere and chromosphere.

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“…The frictions on Li + ions from electrons (equation ( 63) in KK15) are similar and those from neutral hydrogen (cf. Krstić & Schultz 2009) are expected to change slightly only within a reduced mass factor. Therefore, the chemical separation effectively operates and 6 Li + ions move in a strong coupling with electrons.…”

Section: Introductionmentioning

confidence: 99%

Initial Li Abundances in the Proto-Galaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation

Kusakabe

Kawasaki

2019

ApJL

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The chemical separation of Li + ions induced by a magnetic field during the hierarchical structure formation can reduce initial Li abundances in cosmic structures. It is shown that cosmological reionization of neutral Li atoms quickly completes as soon as the first star is formed. Since almost all Li is singly ionized during the main course of structure formation, it can efficiently separate from gravitationally collapsing neutral gas. The separation is more efficient in smaller structures which formed earlier. In the framework of the hierarchical structure formation, extremely metal-poor stars can have smaller Li abundances because of their earlier formations. It is found that the chemical separation by a magnetic field thus provides a reason that Li abundances in extremely metal-poor stars are lower than the Spite plateau and have a large dispersion as well as an explanation of the Spite plateau itself. In addition, the chemical separation scenario can explain Li abundances in NGC 6397 which are higher than the Spite plateau. Thus, Li abundances in metal-poor stars possibly keep information on the primordial magnetic field and the structure formation history.

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Mean free paths and elastic and related transport cross sections for neutrals and singly charged ions of Li, Be, and B in hydrogen plasmas

Cited by 10 publications

References 29 publications

Numerical estimates of the ITER first mirrors degradation due to atomic fluxes

Numerical estimates of the ITER first mirrors degradation due to atomic fluxes

Magnetic-diffusion-driven shear instability of solar flux tubes

Initial Li Abundances in the Proto-Galaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation

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