Classical Nonideal Plasmas Research Articles

Stability of hydrogen atom in non-ideal classical plasmas

The stability of a hydrogen atom embedded in classical nonideal plasma has been investigated. The interaction potential between the proton and the electron has been modeled by a pseudopotential, which is obtained from a sequential solution of Bogolyubov chain equations. The critical values of the plasma screening parameters have been determined quite accurately within the framework of the Rayleigh-Ritz variational method by employing an extensive wave function following a definitive prescription. Convergence of the results has been corroborated by increasing the number of terms in the wave function. A detailed study has been carried out on the effects of nonideality of plasma on the bound states for the density and temperature lying in the ranges of 2.7 × [1023–1026] m−3 and [104–105] K, respectively. It is found that the atom remains bound in the aforementioned density and temperature ranges.

Influence of collective nonideal shielding on fusion reaction in partially ionized classical nonideal plasmas.

The collective nonideal effects on the nuclear fusion reaction process are investigated in partially ionized classical nonideal hydrogen plasmas. The effective pseudopotential model taking into account the collective and plasma shielding effects is applied to describe the interaction potential in nonideal plasmas. The analytic expressions of the Sommerfeld parameter, the fusion penetration factor, and the cross section for the nuclear fusion reaction in nonideal plasmas are obtained as functions of the nonideality parameter, Debye length, and relative kinetic energy. It is found that the Sommerfeld parameter is suppressed due to the influence of collective nonideal shielding. However, the collective nonideal shielding is found to enhance the fusion penetration factor in partially ionized classical nonideal plasmas. It is also found that the fusion penetration factors in nonideal plasmas represented by the pseudopotential model are always greater than those in ideal plasmas represented by the Debye-Hückel model. In addition, it is shown that the collective nonideal shielding effect on the fusion penetration factor decreases with an increase of the kinetic energy.

Collective and Screening Effects on Entanglement Fidelity in Elastic Collisions in Nonideal Plasmas

The nonideal collective and plasma screening effects on the entanglement fidelity in elastic collisions are investigated in classical nonideal plasmas. The entanglement fidelity in nonideal plasmas is obtained as a function of the nonideality plasma parameter, Debye length, and collision energy. It is found that the plasma screening effect significantly increases the entanglement fidelity, especially for low collision energies. The entanglement fidelity is found to decrease with increasing collision energy. It is also found that the collective effect enhances the entanglement fidelity in nonideal plasmas.

On the effect of runaway electrons in dense plasma

AbstractThe effect of runaway electrons has been studied in this work. There were derived the conditions runaway electrons, the influence of electric field on the electron velocity distribution is considered for nonideal classical plasma models. The dependence of friction force on electrons on their velocities,electron‐ion collision frequency as a function of the coupling parameter and the strength of critical electric field on particle density and temperature are determined. The results are compared with the asymptotic theory. It has been shown that for the definite density and temperature ranges the difference between critical electric field values is essential for various plasma models. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Collective correlation and screening effects on radiative recombination in classical nonideal plasmas

Collective correlation and plasma screening effects on the K-shell radiative recombination of the free electron with the ion in classical nonideal plasmas are investigated. The radiative recombination cross section is obtained by the principle of detailed balance with the photoionization cross section of the hydrogenic ion in nonideal plasmas. It is found that the collective and plasma screening effects significantly reduce the radiative recombination cross section in nonideal plasmas. It is also found that the collective and screening effects on the recombination cross section is almost independent of the projectile energy.

Nonideal effects on occurrence scattering time in classical nonideal plasmas

Nonideal plasma screening effects on the occurrence time advance for the elastic electron–ion collisions in classical nonideal plasmas are investigated using the eikonal method. An effective pseudopotential model taking into account the plasma screening and collective effects is applied to describe the electron–ion interaction potential in nonideal plasmas. It is found that the nonideal effect reduces the occurrence time advance. The scattering occurrence time gets stronger time advances with increasing the scattering angle. For small scattering angles, the domain of the nonideality plasma parameter (γ) for the minimum occurrence time advance is found to be 1<γ<3.5.

Orientation phenomena for electron–ion collisional excitations in a classical nonideal plasma

Orientation phenomena for direct 1s → 2p±1 excitations in electron–hydrogenic-ion collisions are investigated in a classical nonideal plasma. An effective pseudopotential model taking into account plasma-screening and collective effects is applied to describe the interaction potential in a nonideal plasma. The orientation parameter for direct 1s → 2p±1 excitations in a nonideal plasma is obtained as a function of the impact parameter, the nonideal-plasma parameter, the Debye length, and the projectile energy. The result shows that the nonideal effect reduces the propensity of the 1s → 2p−1 transition. It is also found that the nonideal effect on the orientation parameter increases with increasing projectile energy.

Non-ideal effects on screening and antiscreening channelsfor ion-ion collisional excitations in non-ideal plasmas

Screening and antiscreening channels for ion-ion collisionalexcitations in classical non-ideal plasmas are investigated. Theinteraction potential in non-ideal plasmas is represented by apseudopotential model. The semiclassical trajectory method isapplied to the path of the projectile ion in order to allowvisualization of the excitation probability as a function of theimpact parameter, projectile energy, and non-ideality plasmaparameter. The semiclassical excitation probability is found todecrease with increasing non-ideal effect. It is also found thatthe non-ideal effect on the excitation probability increases withincreasing collision energy. The non-ideal effect on theantiscreening channel is found to be more significant than that onthe screening channel.

Coulomb logarithm of a nonideal plasma

The Coulomb logarithm is a fundamental plasma parameter in kinetic theory. The traditional formula for the Coulomb logarithm does not correctly account for collisional processes in systems because it is obtained by using an unscreened Coulomb potential. In the present work, the Coulomb logarithm is derived on the basis of a strongly screened pair effective potential. The effective potential takes into consideration long-range many-particle screening effects. An analytical interpolation expression for the Coulomb logarithm is obtained. This formula could be used for further calculations of kinetic properties of classical nonideal plasma.

Classical Electron-Ion Coulomb Bremsstrahlung in Nonideal Plasmas

Classical electron-ion Coulomb bremsstrahlung process is investigated in classical nonideal plasmas using effective pseudopotential model taking into account the plasma screening and collective effects. The straight-line trajectory method is applied to the motion of the projectile electron in order to visualize the variation of the differential bremsstrahlung radiation cross section (DBRCS) as a function of the scaled impact parameter, nonideal plasma parameter, projectile energy, photon energy, and Debye length. The results show that the DBRCS in ideal plasmas described by the Debye-Huckel potential is always greater than that in nonideal plasmas, i.e., the collective effects reduce the DBRCS for both the soft and hard photon cases. For large impact parameters, the DBRCS for the soft photon case is found to be always greater than that for the hard photon case.

K-shell photoionizations in classical nonideal plasmas

Collective and plasma screening effects on photoionization cross sections from the 1s state of hydrogenic ions in classical nonideal plasmas are investigated. An effective pseudopotential model taking into account the collective and plasma screening effects is applied to describe the interaction potential in nonideal plasmas. The screened atomic wave function and energy eigenvalue for the ground state of the hydrogenic ion in classical nonideal plasmas are obtained by the Ritz variational method. The photoionization cross section is obtained by the acceleration form of the transition matrix element in order to investigate the collective and plasma screening effects on the interaction potential. The retardation and Coulomb correction effects are also considered in nonideal plasmas. The total correlation effect is obtained as a function of the nonideality plasma parameter, Debye length, and incident photon energy. The result shows that the collective effect significantly reduces the photoionization cross section. It is also found that the collective effect on the photoionization cross section is increased with increasing the incident photon energy.

Resonant Compton scattering of photons from hydrogenic ions in nonideal plasmas

Plasma screening and collective effects on the resonant Compton scattering of photons by bound atomic electrons from the hydrogenic ions in classical nonideal plasmas are investigated. An effective pseudopotential model taking into account the plasma screening and collective effects is applied to describe the interaction potential in nonideal plasmas. The screened wave functions and energy eigenvalues for the ground and excited states of the target ion are obtained by the Ritz variational method. The nonperturbative expression for the transition matrix element near resonance is obtained by the basic lowest-order photon-perturbation Hamiltonian in the electronic dipole representation. It is found that the resonant Compton scattering cross section including the plasma screening effect is greater than the cross section neglecting the plasma screening effect. It is also found that the collective effect increases the Compton cross section at the resonance.

Electron-impact ionization in classical nonideal plasmas

Electron-impact ionization of hydrogenic ions is investigated in classical nonideal plasmas. The projectile–target interaction potential in classical nonideal plasmas is represented by the pseudopotential model. Semiclassical trajectory method is applied to the path of the projectile electron in order to visualize the ionization probability as a function of the impact parameter. The semiclassical ionization probability decreases with increasing the collective effect. It is also found that the collective effect increases with increasing the projectile energy.

Electron captures by positrons from hydrogenic ions in nonideal classical plasmas

In nonideal classical plasmas, the electron captures by positrons from hydrogenic ions are investigated. An effective pseudopotential model taking into account the plasma screening effects and collective effects is applied to describe the interaction potential in nonideal plasmas. The classical Bohr-Lindhard model has been applied to obtain the electron capture radius and electron capture probability. The modified hyperbolic trajectory method is applied to the motion of the projectile positron in order to visualize the electron capture probability as a function of the impact parameter, nonideal plasma parameter, projectile velocity, and plasma parameters. The results show that the electron capture probability in nonideal plasmas is always greater than that in ideal plasmas descried by the Debye-Huckel potential, i.e., the collective effect increases the electron capture probability. It is also found that the collective effect is decreased with increasing the projectile velocity.

Semiclassical inelastic electron-ion collisional excitations in nonideal plasmas

Semiclassical electron-hydrogenic ion collisional excitation cross sections for 1s→2s and 1s→2p0 in nonideal plasmas are obtained. An effective pseudopotential model taking into account the plasma screening and collective effects is applied to describe the electron-ion interaction potential in a classical nonideal plasma. The semiclassical straight-line trajectory approximation is applied to the motion of the projectile electron in order to investigate the variation of the total inelastic scattering cross section as a function of the projectile energy, nonideal plasma parameter, and Debye length. It is found that the transition probabilities in ideal plasmas described by the Debye–Hückel potential model are greater than those in nonideal plasmas described by the pseudopotential model. The maximum position of the transition probability gets closer to the target core as the projectile energy increases. It is also found that the scaled cross section decreases when the nonideal plasma parameter (γ) is increased, i.e., the nonideality of plasmas reduces the electron-ion collision cross section.

Electron-ion Coulomb Bremsstrahlung in nonideal plasmas

The classical electron-ion Coulomb Bremsstrahlung process is investigated in nonideal plasmas. An effective pseudopotential model taking into account the plasma screening and collective effects is applied to describe the electron-ion interaction potential in a classical nonideal plasma. The classical straight-line trajectory method is applied to the motion of the projectile electron in order to visualize the variation of the differential Bremsstrahlung radiation cross-section (DBRCS) as a function of the scaled impact parameter, nonideal plasma parameter, projectile energy, photon energy, and Debye length. The results show that the DBRCS in ideal plasmas described by the Debye-Huckel potential is always greater than that in nonideal plasmas, i.e., the collective effects reduce the DBRCS for both the soft and hard photon cases. For large impact parameters, the DBRCS for the soft photon case is found to be always greater than that for the hard photon case.

Semiclassical electron captures by protons from hydrogenic ions in nonideal classical plasmas

Electron capture processes by protons from hydrogenic ions in nonideal classical plasmas are investigated in accordance with a semiclassical version of the Bohr–Lindhard model using the impact parameter method. The screened electron capture radius is obtained by using the effective pseudopotential model, taking into account the plasma screening effect and the collective effect. The scaled semiclassical electron capture probability is obtained as a function of the impact parameter, nonideal plasma parameter, Debye length, and projectile velocity. The nonideal plasma effect on the scaled semiclassical capture probability for the intermediate energy projectile is found to be more significant than that for the high energy projectile. The maximum position of the electron capture probability is getting close to the target ion as the nonideal plasma parameter increases.

Eikonal scattering cross section for elastic electron–ion collisions in nonideal plasmas

Modified eikonal approximation is applied to investigate the elastic electron–ion collisions in nonideal plasmas. An effective pseudopotential model, taking into account the plasma screening and collective effects, is applied to describe the electron–ion interaction potential in a classical nonideal plasma. The semiclassical straight-line trajectory approximation is applied to the motion of the projectile electron in order to investigate the variation of the total elastic scattering cross section as a function of the projectile energy, nonideal plasma parameter, and Debye length. The results show that the scaled total cross section in ideal plasmas described by the Debye–Hückel potential model is found to be greater than that in nonideal plasmas described by the pseudopotential model. It is also found that the scaled cross section is decreased with increasing the nonideal plasma parameter (γ), i.e., the nonideality of plasmas reduces the electron–ion collision cross section.

Pseudopotential theory of classical non-ideal plasmas

An effective potential (pseudopotential) model of the particle interaction of a classical non-ideal plasma, taking into account collective events in plasma, is proposed.

On the theory of plasma oscillations in a non-ideal classical plasma

Using the diagram technique, a high-frequency expansion (with respect to powers 1/ omega 2) is obtained for polarization operators defining dielectric function of a plasma at arbitrary strong interaction between particles. On this basis the spectrum of plasma oscillations for non-ideal classical one- and two-component plasmas is studied. There is a good agreement with the data of molecular dynamic calculations without using any adjusting parameters. It is shown that the non-Coulombic nature of interaction between particles has a dramatic influence on the description of the spectrum of plasma oscillations in the classical two-component plasma.