Dynamic Plasma Screening Effects Research Articles

Influence of the nonlinear dynamic plasma screening on the electron-dust collision in dusty plasmas

The nonlinear dynamic plasma screening effects on the elastic electron-dust grain collision are investigated in dusty plasmas. The results show that the nonlinear dynamic screening effect significantly increases the magnitude of the eikonal phase shift. It is also found that the magnitude of the phase shift decreases with an increase of the thermal energy. In addition, it is found that the differential eikonal cross section shows the oscillatory behavior, and the oscillating peaks approach to the collision center with increasing thermal energy. It is also found that the total eikonal cross section decreases with an increase of the thermal energy.

Influence of the dynamic plasma screening on the Ramsauer phenomena for the polarization collision in thermal plasmas

The dynamic plasma screening effects on the Ramsauer phenomena for the electron-atom polarization collision are investigated in dense plasmas. The phase theory and the effective Buckingham potential with the dynamic Debye length are employed to obtain the phase shift and total collision cross section as functions of the collision energy, and Debye length, polarizability, scattering length, and thermal energy. The result shows that the energy for the Ramsauer minimum increases with an increase of the thermal energy. It is also found that the dynamic plasma screening effect suppresses the total polarization cross section below the Ramsauer energy. However, it is found that the dynamic plasma screening effect enhances the total polarization cross section above the Ramsauer energy. The screening effect on the Ramsauer energy is also discussed.

Dynamic non-Maxwellian screening effects on elastic collisions in Lorentzian plasmas

Abstract The dynamic plasma screening and non-Maxwellian effects on elastic electron–ion collisions are investigated in generalized Lorentzian distribution plasmas. The eikonal is employed to obtain the eikonal phase as a function of the spectral index, impact parameter, collision energy, thermal energy, and Debye length. The result shows that the non-Maxwellian effect suppresses the eikonal phase. It is found that the dynamic screening effect significantly enhances the elastic collision cross section for the low thermal energy case. In addition, the eikonal collision cross section is increased by the non-Maxwellian effect.

Dynamic plasma screening effects on the occurrence scattering time in nonideal plasmas

Abstract The dynamic plasma screening effects on the occurrence scattering time advance for elastic electron–ion collisions are investigated in nonideal plasmas. The second-order eikonal method is employed to obtain the occurrence scattering time as a function of the impact parameter, projectile energy, thermal energy, and Debye length. The result shows that the occurrence scattering time advance decreases with increasing scattering angle. It is also found that the occurrence scattering time advance increases with increasing thermal energy. In addition, the dynamic screening effect is found to be identical to the static screening effect in the forward direction, i.e., θ = 0 .

Dynamic plasma screening effects on low-energy bremsstrahlung emission in nonideal plasmas

Abstract The dynamic screening effects on the low-energy electron–ion bremsstrahlung process are investigated for both the soft and hard photon radiations in nonideal plasmas. The impact-parameter analysis is employed to obtain the bremsstrahlung radiation cross section as a function of the impact parameter, projectile energy, radiation photon energy, thermal energy, and Debye length. The results show that the dynamic screening effect on the bremsstrahlung radiation is found to be more significant for distant encounters. In addition, the dynamic screening effect is found to be more important for the soft photon radiation and decreases with increasing the radiation photon energy.

Screening effects on dynamic electron captures in nonideal plasmas

The dynamic plasma screening effects on the electron capture process are investigated in nonideal plasmas. The semiclassical version of the Bohr-Lindhard model with the impact parameter method is applied to obtain the electron capture probability in nonideal plasmas as a function of the impact parameter, debye length, thermal energy, and collision energy. The result shows that the electron capture radius and capture probability decrease with the increasing thermal energy. The dynamic screening effects on the capture probability are found to be more significant near the position of the maximum capture probability. It is also found that the electron capture radius and capture probability including the dynamic screening effects are found to be greater than those including the static screening effects.

Dynamic screening effects on atomic ionizations in kappa-Maxwellian plasmas

The dynamic plasma screening effects on the atomic ionization process are investigated in κ-Maxwellian distribution plasmas using the semiclassical analysis. The projectile-target interaction Hamiltonian in the momentum space is obtained by the plasma dielectric function in κ-Maxwellian distribution plasmas. The semiclassical ionization probability is obtained as a function of the impact parameter b, projectile electron energy E, Debye length Λ, spectral index κ, and velocity ratio v∕vTh. It is found that the dynamic screening effect increases for small velocity ratios and decreases for large velocity ratios with the decreasing spectral index.

Dynamic screening effects on semiclassical electron captures in kappa-Maxwellian plasmas

Dynamic plasma screening effects on the electron capture process in kappa-Maxwellian plasmas are investigated using the semiclassical version of the Bohr–Lindhard model. The interaction potential and screened electron capture radius are obtained by considering the longitudinal component of the plasma dielectric function. The semiclassical electron capture probability is also obtained as a function of the impact parameter, Debye length, projectile velocity, and spectral index. It is found that the dynamic screening effects on the electron capture probability are more significant for low projectile energies. The maximum position of the scaled electron capture probability approaches the target nucleus with increasing projectile energy. The dynamic screening effect is also found to decrease with increasing spectral index.

Dynamic screening effects on the electron–ion bremsstrahlung in a kappa-Maxwellian plasma

The dynamic plasma screening effects on classical electron–ion bremsstrahlung processes are investigated in a kappa-Maxwellian distribution plasma using the plasma dielectric function. It is found that the bremsstrahlung radiation cross section increases with increasing the spectral index κ. The result shows that the bremsstrahlung cross section increases with increasing the velocity ratio v/ v ‖. It is also found that the dynamic screening effects are found to be more important for lower spectral indices.

Screening Effects on Electron Capture from Highly Charged Hydrogenic Ions by Protons in Dense Plasmas

Electron capture processes by protons from highly charged hydrogenic ions in dense plasmas including dynamic screening effects are investigated using the semiclassical version of the Bohr–Lindhard model with the straight-line path. The dynamic interaction potential in dense plasmas is obtained by considering the longitudinal component of the plasma dielectric function. The scaled semiclassical electron capture probability is obtained as a function of the impact parameter, Debye length, and projectile velocity. The dynamic plasma screening effect on the scaled semiclassical electron capture probability is found to be more significant for low projectile velocities. When the projectile velocity is smaller than the electron thermal velocity, the dynamic screening effect is weaker than the static screening effect. However, when the projectile velocity is greater than the electron thermal velocity, the dynamic plasma screening effect leads to the static plasma screening effect.

Dynamic plasma screening effects on electron–ion collisional ionizations in a generalized Lorentzian distribution plasma

Dynamic plasma screening effects on semiclassical ionization probabilities for electron-impact ionization of hydrogenic ions are investigated in a generalized Lorenzian (kappa) distribution plasma. The projectile–target interaction Hamiltonian is obtained by introduction of the longitudinal plasma dielectric function. A semiclassical straight-line trajectory method is applied to the path of the projectile electron and the bound electron is treated quantum mechanically. The semiclassical ionization probability is obtained as a function of the impact parameter, projectile energy, spectral index, and Debye length. It is found that the non-Maxwellian effect is quite small for low plasma temperatures. However, the non-Maxwellian effect is significant for high plasma temperatures. It is also found that the dynamic plasma screening effect is increased with decreasing the spectral index.

Dynamic Orientation for Electron-Ion Collisional Excitation in a Maxwellian Plasma

Orientation phenomena for 1s → 2p±1 transitions in electron-ion collisional excitations in dense plasmas are investigated using the dynamic interaction potential. Scaled transition probabilities for 1s → 2p±1 excitations are obtained using the plasma dielectric function. The semiclassical straight-line trajectory approximation is applied to the motion of the projectile electron in order to visualize the variation of the dynamic orientation parameter as a function of impact parameter and collision energy. The propensity of the m = -1 transition including the dynamic plasma screening effect is always greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic plasma screening effect becomes a static plasma screening effect. However, when the projectile velocity is greater than the electron thermal velocity, the propensity of the m = -1 transition in the dynamic model plasma is found to be stronger than that in the static model plasma.

Elastic electron–ion collisions in a Lorentzian plasma

Plasma screening effects on elastic electron–ion collision processes in a Lorentzian (kappa)-distribution plasma are investigated using the eikonal method. The electron–ion interaction potential is obtained by introducing a plasma dielectric function εκ. The semiclassical straight-line trajectory method is applied to the path of a projectile electron in order to investigate the variation of the eikonal phase as a function of impact parameter and spectral index κ. In the first-order eikonal approximation, the dynamic plasma screening effect on the eikonal phase is found to be a static screening effect, and depends only on the Debye length and spectral index. The position of the maximum of the differential elastic eikonal cross-section recedes from the ion core with increasing spectral index. The plasma screening effect on the eikonal cross-section increases with decreasing spectral index.

Electron capture in the Lorentzian distribution plasma

Electron captures from hydrogenic ions by protons in a generalized Lorentzian (kappa) velocity distribution plasma are investigated using the semiclassical Bohr–Lindhard model. The potential energy between the projectile ion and the released electron is obtained by introduction of the plasma dielectric function. The straight-line trajectory approximation is applied to the motion of the projectile ion in order to obtain the electron capture probability as a function of impact parameter, collision energy, and spectral index κ. It is found that the semiclassical capture probability including the dynamic plasma screening effect is increased with increasing the spectral index. The plasma screening effects on the electron capture probabilities are found to be more effective for low projectile velocities. It is also found that the dynamic plasma screening effect on the electron capture probability in the Lorentzian distribution plasma is stronger than that in the Maxwellian distribution plasma since the effective Debye length in the Lorentzian plasma is smaller than the Debye length in the Maxwellian plasma.

Dynamic plasma screening effects on electron-ion Coulomb bremsstrahlung in the Lorentzian distribution plasma

Dynamic plasma screening effects are investigated on classical bremsstrahlung electron-ion Coulomb scattering in a generalization Lorentzian (kappa) velocity distribution plasma. The electron-ion interaction potential is obtained by introduction of the plasma dielectric function. A semiclassical straight-line trajectory method is applied to the path of the projectile electron. The results show that the differential bremsstrahlung radiation cross section including the dynamic plasma screening effect is increased as an increase of the spectral index κ. In other words, the radiation spectrum in a thermal distribution plasma is found to be stronger than that in the nonthermal distribution plasma. It is also found that the plasma screening effects on the bremsstrahlung are more effective for the hard photon radiation. When the projectile velocity is greater than the electron thermal velocity, then, the interaction potential is almost unshielded.

Dynamic plasma screening effects on semiclassical electron captures from hydrogenic ions by protons in weakly coupled plasmas

Electron capture processes by protons from hydrogenic ions in dense plasmas, including dynamic screening effects, are investigated using the semiclassical version of the Bohr and Lindhard model with the straight-line trajectory method. The dynamic interaction potential and screened electron radius are obtained by considering the longitudinal component of the plasma dielectric function. The scaled semiclassical electron capture probability is obtained as a function of the impact parameter, Debye length, and projectile velocity. The plasma screening effects on the target system is known to be quite small, so that the plasma screening effects on the capture probability is mainly determined by the screened capture radius. The dynamic screening effect on the scaled semiclassical capture probability is found to be more significant for low projectile velocities. When the projectile velocity is smaller than the electron thermal velocity, the dynamic screening effect is weaker than the static screening effect. However, when the projectile velocity is greater than the electron thermal velocity, the dynamic screening effect leads to the static screening effect. The maximum position of the scaled capture probability approaches to the target nucleus as an increase of the projectile energy.

Dynamic plasma screening effects on electron–ion collisional excitations in a generalized Lorenzian (kappa) distribution plasma

Dynamic plasma screening effects are investigated on 1s→2p dipole transition probabilities for electron-impact excitation of hydrogenic ions in a generalized Lorenzian (kappa) velocity distribution plasmas. The electron–ion interaction potential is obtained by introduction of the plasma dielectric function. A semiclassical straight-line trajectory method is applied to the path of the projectile electron in order to visualize the dynamic plasma screening effects on the semiclassical transition probabilities as a function of the impact parameter and the collision energy. The transition probability including the dynamic plasma screening effect is found to be always greater than that including the static plasma screening effects. It is also found that the dynamic plasma screening effects on the electron–ion collisional excitations in the Lorenzian velocity distribution plasmas are more effective than those in the Maxwellian velocity distribution plasmas.

Dynamic screening effects on antiscreening excitations for ion–ion collisions in dense plasma

In dense plasmas, dynamic plasma screening effects are investigated on antiscreening channels for excitation of a one-electron ion target by a one-electron ion projectile. The ion–ion interaction potential is considered by the introduction of the longitudinal plasma dielectric function. A semiclassical straight-line trajectory method is applied to the ion projectile path in order to visualize the dynamic plasma screening effects on the transition probabilities in dense plasmas as a function of the impact parameter and the collision energy. The transition probabilities including the dynamic plasma screening effects are found to always be greater than those including the static plasma screening effects. When the projectile velocity is greater than the 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 also found that the quadrupole transitions (dipole-quadrupole and quadrupole–quadrupole) show the double peaks due to the node of the 2s radial wave function.

Plasma screening effects on eikonal phase for electron-ion elastic collisions in weakly coupled plasmas

Eikonal approximation is applied to investigate elastic electron-ion collisions in weakly coupled plasmas. Plasma screening effects on eikonal phase are investigated for eikonal differential elastic scattering cross sections. The electron-ion interaction potential in weakly coupled plasmas has been obtained by the introduction of the longitudinal plasma dielectric function. The semiclassical straight-line trajectory method is applied to the path of the projectile electron in order to investigate the variation of the eikonal phase as a function of the impact parameter and the plasma parameters. In the first-order eikonal approximation, the dynamic plasma screening effect is identical to the static screening effect obtained by the Debye–Hückel potential. The eikonal differential elastic cross section substantially decreases with an increase in the projectile energy and increases as the plasma screening effect decreases through the Debye length. The plasma screening effects are more significant for large impact parameters.

Dynamic plasma screening effects on electron capture process in hydrogenic ion–fully stripped ion collisions in dense plasmas

In dense plasmas, dynamic plasma screening effects are investigated on electron capture from hydrogenic ions by past fully stripped ions. The classical Bohr–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 static 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–Hückel model overestimates the plasma screening effects on the electron capture processes in dense plasmas.