Cobalt-Hydrogen Atomic and Ionic Collisional Data

Rate coefficients for inelastic processes in low-energy Co + H, Co + + H − , Co + + H , and Co 2 + + H − collisions are estimated using the quantum simplified model. Considerations include 44 triplet and 55 quintet molecular states of CoH, as well as 91 molecular states of CoH + . The estimations provide the rate coefficients for the 4862 partial processes (mutual neutralization, ion-pair formation, excitation, and de-excitation) in the neutral CoH system, and for the 8190 partial processes in the ionized CoH + system, 13 , 052 processes in total. At T = 6000 K, the rate coefficients with the largest values around 6 × 10 − 8 cm 3 s − 1 correspond to the mutual neutralization processes into the Co ( e 2 F ) + H and Co + ( g 5 F ) + H final channels in the neutral and ionized systems, respectively. Among the excitation and de-excitation processes in Co + H and in Co + + H collisions, at T = 6000 K, the largest rate coefficients have values around 7 × 10 − 9 cm 3 s − 1 and correspond to the processes Co ( y 2 S ∘ ) + H → Co ( e 2 F ; v 4 D ∘ ) + H and Co + ( h 3 P ) + H → Co + ( g 3 P ; g 5 P ; g 5 F ) + H , respectively. The calculations single out inelastic processes important for non-local thermodynamic equilibrium (NLTE) modelling of Co I and Co II spectra in stellar atmospheres. The test NLTE calculations are carried out, and it is found that the new collision rates have a strong effect on the line formation and NLTE abundance corrections.

A 1D kinetic model for cosmic microwave background comptonization

This work presents a novel derivation of the expressions that describe the distortions of the CMB curve due to the interactions between photons and the electrons present in dilute ionized systems. In this approach, a simplified a one-dimensional evolution equation for the photon number occupation is applied in order to describe the aforemationed interaction. This methodology allows to emphasize the physical features ot the Sunyaev-Zeldovich effect and suggests the existence of links between basic statistical physics and complex applications involving radiative processes.

Core-polarization corrected relativistic energies and radiative data for one-electron spectra of Bi V through U XIV

The relativistic core-polarization corrected Dirac–Fock energy levels, oscillator strength, and lifetimes are predicted for highly ionized spectra of gold isoelectronic sequence from Bi V through U XIV. It is demonstrated that core polarization (core–valence electron correlation) strongly affects oscillator strengths and lifetimes of 6s–6p, 6p–5d, and 6d–5f transitions (the latter particularly in the vicinity of the collapse region) even for highly ionized systems of gold isoelectronic sequence.

Plasma Parameters and Weakly Non-Ideal Behaviour of a High Density, Super-Atmospheric 2kA Cascade Arc in Argon

Experimental results are reported for simultaneous pressure and current pulses up to 14 bar and 2200 A superimposed on an atmospheric pressure 60 A dc cascade arc. A current density over 108 A/m2, previously 107 A/m2 (power density 1012W m3, previously 1010W/m3) has been ob­tained. The electron temperature of the thermal plasma was deduced from the end-on measured radiance of argon lines, and the electron density from the absolute continuum emission. The values found for the quantities mentioned during the quasi-stationary phase of the current pulse, lasting ~ 1 ms, were 27000 K and 3 · 1023 m-3, respectively, at a pressure of ~ 1.5 bar (ionization degree 100%), and 18000 K and > 1024 m-3, respectively, for a pressure of 14 bar (ionization degree 60%). These values satisfy the LTE relation. Deviations from the Spitzer conductivity have been observed in this weakly non-ideal plasma.In general, the high ionized thermal plasma studied with its composition of neutral, singly ionized and doubly ionized argon atoms can serve as a useful medium for spectroscopic studies of highly ionized systems and as a valuable source of radiation in the visible a well as in the near and far ultraviolet parts of the spectrum.