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Title: Charge exchange and ionization in hydrogen atom-fully stripped ion collisions in Debye plasmas

Abstract

The processes of charge exchange and ionization in collisions of ground state hydrogen atom with fully stripped ions in a weakly coupled plasma are studied by the classical trajectory Monte Carlo method in the collision energy range 10-900 keV/amu. The interparticle interactions are described by the Debye-Hueckel model with inclusion of dynamical effects associated with the projectile velocity. The microcanonical distribution of initial state electronic coordinates and momenta has been determined by inclusion of plasma screening effects. The cross section dependencies on plasma parameters and ion charge and velocity are investigated. It is shown that plasma effects on charge exchange and ionization cross sections are significant and particularly pronounced at low collision velocities. The results of systematic cross section calculations for different values of Debye screening length (in the range 1-50a{sub 0}) and ion charges (in the range 1-14) are presented.

Authors:
; ; ; ;  [1];  [2]
  1. Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China)
  2. (Macedonia, The Former Yugoslav Republic of)
Publication Date:
OSTI Identifier:
20975012
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2736675; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ATOMS; CHARGE EXCHANGE; GROUND STATES; HYDROGEN; ION COLLISIONS; IONIZATION; IONS; KEV RANGE; MONTE CARLO METHOD; PLASMA; PLASMA SIMULATION; VELOCITY

Citation Formats

Zhang, H., Wang, J. G., He, B., Qiu, Y. B., Janev, R. K., and Macedonian Academy of Sciences and Arts, P.O. Box 428, 1000 Skopje. Charge exchange and ionization in hydrogen atom-fully stripped ion collisions in Debye plasmas. United States: N. p., 2007. Web. doi:10.1063/1.2736675.
Zhang, H., Wang, J. G., He, B., Qiu, Y. B., Janev, R. K., & Macedonian Academy of Sciences and Arts, P.O. Box 428, 1000 Skopje. Charge exchange and ionization in hydrogen atom-fully stripped ion collisions in Debye plasmas. United States. doi:10.1063/1.2736675.
Zhang, H., Wang, J. G., He, B., Qiu, Y. B., Janev, R. K., and Macedonian Academy of Sciences and Arts, P.O. Box 428, 1000 Skopje. Tue . "Charge exchange and ionization in hydrogen atom-fully stripped ion collisions in Debye plasmas". United States. doi:10.1063/1.2736675.
@article{osti_20975012,
title = {Charge exchange and ionization in hydrogen atom-fully stripped ion collisions in Debye plasmas},
author = {Zhang, H. and Wang, J. G. and He, B. and Qiu, Y. B. and Janev, R. K. and Macedonian Academy of Sciences and Arts, P.O. Box 428, 1000 Skopje},
abstractNote = {The processes of charge exchange and ionization in collisions of ground state hydrogen atom with fully stripped ions in a weakly coupled plasma are studied by the classical trajectory Monte Carlo method in the collision energy range 10-900 keV/amu. The interparticle interactions are described by the Debye-Hueckel model with inclusion of dynamical effects associated with the projectile velocity. The microcanonical distribution of initial state electronic coordinates and momenta has been determined by inclusion of plasma screening effects. The cross section dependencies on plasma parameters and ion charge and velocity are investigated. It is shown that plasma effects on charge exchange and ionization cross sections are significant and particularly pronounced at low collision velocities. The results of systematic cross section calculations for different values of Debye screening length (in the range 1-50a{sub 0}) and ion charges (in the range 1-14) are presented.},
doi = {10.1063/1.2736675},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The plasma screening effects of dense quantum plasmas on charge exchange processes of a fully stripped ion colliding with a hydrogen atom are studied by the classical trajectory Monte Carlo method. The inter-particle interactions are described by the exponential cosine-screened Coulomb potentials. It is found that in weak screening conditions, cross sections increase with the increase of the ionic charge Z. However, in strong screening conditions, the dependence of cross sections on the ionic charge is related to the incident particle energy. At high energies, cross sections show a linear increase with the increase of Z, whereas at low energies,more » cross sections for Z≥4 become approximately the same. The He{sup 2+} and C{sup 6+} impacting charge exchange cross sections in dense quantum plasmas are also compared with those in weakly coupled plasmas. The interactions are described by the static screened Coulomb potential. It is found that for both He{sup 2+} and C{sup 6+}, the oscillatory screening effects of dense quantum plasmas are almost negligible in weak screening conditions. However, in strong screening conditions, the oscillatory screening effects enhance the screening effects of dense quantum plasmas, and the enhancement becomes more and more significant with the increase of the screening parameter and the ionic charge.« less
  • The existing theoretical cross section data for the charge exchange process of multiply charged fully stripped ions with hydrogen atoms are evaluated in the energy range from approx.10 eV/u to approx.10/sup 3/ keV/u. The evaluation has been performed on the basis of both pure theoretical arguments and comparison with the most accurate experimental cross sections. The ionic charge state ranges from Z = 2 to Z = 54. The theoretical methods for calculation of the charge exchange cross sections are briefly discussed, and their regions of validity and the accuracy of the produced data are assessed.
  • The charge transfer and ionization cross sections have been calculated for He-like system (Li{sup +}, Be{sup 2+}, B{sup 3+}, C{sup 4+}, N{sup 5+}, O{sup 6+}) and hydrogen atom collisions in Debye plasmas for energies ranging from 1 to 500 keV using the classical trajectory Monte Carlo method. Interactions of the active electrons with the projectile ions have been described by model potentials. Cross sections are determined in both screening and unscreening environments, and a comparative study between both environments has been carried out. In particular, an interesting feature of sudden increase in the ionization cross sections at lower velocities ismore » also observed in all the systems like pandey et al.[M. K. Pandey et al., Phys. Plasmas 19, 062104 (2012)] calculations for O{sup 8+}+ H collision. The feature of sudden increase in ionization cross sections at lower velocities and the effect of plasmas condition on it are explained in terms of the classical trajectory framework. We have found the cross sections for both capture and ionization are dependence on Debye screening lengths throughout the collision energies range, but are particularly pronounced at low projectile collisions energies. The calculated cross sections for the unscreened case are found in reasonable agreement with available experimental and theoretical results.« less
  • The existing theoretical cross section data for charge exchange of partially stripped ions on atomic hydrogen are evaluated in the energy range from approx.10 eV/u to approx.10/sup 3/ keV/u. The evaluation has been carried out by using both pure theoretical arguments and comparison with the most accurate experimental data. Ions with atomic numbers Z = 3--8, 10, 12, 13, 14, 16, 18, 22, 26, 30, 36, 41, 42, 48, 54, 73, and 74, in charge states q between q = 2 and q = (Z-1), have been examined. A brief discussion of the evaluation criteria is also given.
  • In dense plasmas, dynamic plasma screening effects are investigated on electron capture from hydrogenic ions by past fully stripped ions. The classical Bohr{endash}Lindhard model has been applied to obtain the electron capture probability. The interaction potential in dense plasmas is represented in terms of the longitudinal dielectric function. The classical straight-line trajectory approximation is applied to the motion of the projectile ion in order to visualize the electron capture probability as a function of the impact parameter, projectile energy, and plasma parameters. The electron capture probability including the dynamic plasma screening effect is always greater than that including the staticmore » plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. When the projectile velocity is greater than the plasma electron thermal velocity, the interaction potential is almost unshielded. The difference between the dynamic and static plasma screening effects is more significant for low energy projectiles. It is found that the static screening formula obtained by the Debye{endash}H{umlt u}ckel model overestimates the plasma screening effects on the electron capture processes in dense plasmas. {copyright} {ital 1997 American Institute of Physics.}« less