Relaxation of non-isothermal hot dense plasma parameters

The relaxation of temperature,coupling parameters,the excess part of equation of state,and the correlation energy of the non-isothermal hot dense plasmas are considered on the basis of the method of effective interaction potentials.The electroneion effective interaction potential for the hot dense plasma is discussed.The accuracy of description of the dense plasma properties by the effective electroneion interaction potential is demonstrated by the agreement of the derived quantities like stopping power and transport coefficients calculated using our methodology with the results of the finite-temperature Kohn-Sham density-functional theory molecular dynamics,and orbital-free molecular dynamics results as well as with the data obtained using other theoretical approaches.

Investigation of Al plasmas from thin foils irradiated by high-intensity extreme ultraviolet

Dynamics and spectral transmission of Al plasma produced by extreme ultraviolet(EUV)irradiation of 0.75-mm thick Al foil is investigated.The EUV radiation with the peak power density in the range of 0.19-0.54 TW/cm 2 is provided by Z-pinch formed by W multiwire array implosion in the Angara-5-1 facility.Geometry of the experiment ensures that there are no plasma fluxes from the pinch toward the Al foil and plasma.The same EUV source is used as a back illuminator for obtaining the absorption spectrum of Al plasma in the wavelength range of 5e24 nm.It comprises absorption lines of ions Al^(4+),Al^(5+),Al^(6+),Al^(7+).Analysis of relative intensities of the lines shows that those ions are formed in dense Al plasma with a temperature of~20 eV.Dynamics of Al plasma has been investigated with transverse laser probing.We have also performed radiation-gas-dynamics simulations of plasma dynamics affected by external radiation,which includes self-consistent radiation transport in a plasma shell.The simulations show good agreement with an experimental absorption spectrum and with experimental data concerning plasma dynamics,as well as with the analysis of line absorption spectrum.This confirms the correctness of the physical model underlying these simulations.

Time-Resolved Transmission Measurements of Warm Dense Iron Plasma

Transmission measurements of warm dense iron plasma are reported over the photon energy range of 400-1200 e V, including the strong 2p-3d structures. One-dimensional hydrodynamic simulation is performed to estimate the plasma conditions： temperatures of several eV and densities of about O. 1 g/cm3. By using the simulated tempera- ture and density, the calculations of the transmission spectra are performed and compared with the time-resolved experimental results.

Ground-State Energy Shifts of H-Like Ti Under Dense and Hot Plasma Conditions

In this study, by adopting the ion sphere model, the self-consistent field method is used with the Poisson-Boltzmann equation and the Dirac equation to calculate the ground-state energies of H-like Ti at a plasma electron density from 10^22 cm^-3 to 10^24 cm^-3 and the electron temperature from 100 eV to 3600 eV. The ground-state energy shifts of H-like Ti show different trends with the electron density and the electron temperature. It is shown that the energy shifts increase with the increase in the electron density and decrease with the increase in the electron temperature. The energy shifts are sensitive to the electron density, but only sensitive to the low electron temperature. In addition, an accurately fitting formula is obtained to fast estimate the ground-state energies of H-like Ti. Such fitted formula can also be used to estimate the critical electron density of pressure ionization for the ground state of H-like Ti.

Nuclear Fusion Within Extremely Dense Plasma Enhanced by Quantum Particle Waves

Quantum effects play an enhancement role in p-p chain reactions occurring within stars. Such an enhancement is quantified by a wave penetration factor that is proportional to the density of the participating fuel particles. This leads to an innovative theory for dense plasma, and its result shows good agreement with independent data derived from the solar energy output. An analysis of the first Z-pinch machine in mankind＇s history exhibiting neutron emission leads to a derived deuterium plasma beam density greater than that of water, with plasma velocities exceeding 10000 km/s. Fusion power could be achieved by the intersection of four such pinched plasma beams with powerful head-on collisions in their common focal region due to the beam and target enhanced reaction.

Dense positrons and γ-rays generation by lasers interacting with convex target

We use quantum electrodynamics particle-in-cell simulation to study the generation of dense electron–positron plasma and strongγ-ray bursts in counter-propagating laser beam interactions with two different solid targets,i.e.planar(type I)and convex(type II).We find that type II limits fast electron flow most effectively.while the photon density is increased by about an order of magnitude and energy by approx.10%–20%compared with those in type I target.γ-photon source with an ultrahigh peak brilliance of 2?×?1025 photons/s/mm2/mrad2/0.1%BW is generated by nonlinear Compton scattering process.Furthermore,use of type II target increases the positron density and energy by 3 times and 32%respectively,compared with those in type I target.In addition,the conversion efficiencies of total laser energy toγ-rays and positrons of type II are improved by 13.2%and 9.86%compared with type I.Such improvements in conversion efficiency and positron density are envisaged to have practical applications in experimental field.

Shock Wave and Particle Velocities of Typical Metals on Shock Adiabats

The high-pressure shock wave data obtained in underground nuclear tests and high-power laser experiments are analyzed using a three-term equation of state and the Hugoniot relationship. Apart from the good agreement of the predicted results with experimental data related to samples Pb, Cu, and Au, an obvious deviation of the experimental data of the Fe sample from the corresponding numerical ones is found, and various comparisons of the data imply that the errors are likely to occur in the measurement rather than in the theoretical prediction. Plentiful data pertaining to a set of metal materials on shock adiabats reveal that there exists an asymptotic parabolic relationship between shock pressure or temperature and particle velocity for very strong shock waves, in contrast to the experimentally well-known linear relationship between shock wave velocity and particle velocity. All these are expounded physically in detail.

Pulsed high-current discharge in water:adiabatic model of expanding plasma channel and acoustic wave

This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium.A discharge with a current amplitude of 10 kA,a duration of 400 ns,and an amplitude pulsed power of 280 MW in water at atmospheric pressure created an expanding acoustic wave with an amplitude of more than 100 MPa.To describe the formation of the discharge channel,an isothermal plasma model has been developed,which made it possible to calculate both the expansion dynamics of a high-current channel and the strong acoustic wave generated by it.Our calculations show that the number density of plasma in the channel reaches 10^(20) cm^(-3),while the degree of water vapor ionization is about 10%,and the channel wall extends with a velocity of 500 m s^(−1).The calculations for the acoustic wave are in good agreement with measurements.

Mechanical properties of Al/a-C nanocomposite thin films synthesized using a plasma focus device

The Al/a-C nanocomposite thin films are synthesized on Si substrates using a dense plasma focus device with alu- minum fitted anode and operating with CH4/Ar admixture. X-ray diffractometer results confirm the formation of metallic crystalline Al phases using different numbers of focus shots. Raman analyses show the formation of D and G peaks for all thin film samples, confirming the presence of a-C in the nanocomposite thin films. The formation of Al/a-C nanocomposite thin films is further confirmed using X-ray photoelectron spectroscopy analysis. The scanning electron microscope results show that the deposited thin films consist of nanoparticles and their agglomerates. The sizes of th agglomerates increase with increasing numbers of focus deposition shots. The nanoindentation results show the variations in hardness and elastic modulus values of nanocomposite thin film with increasing the number of focus shots. Maximum values of hardness and elastic modulus of the composite thin film prepared using 20 focus shots are found to be about 10.7 GPa and 189.2 GPa, respectively.

Structural and mechanical properties of Al–C–N films deposited at room temperature by plasma focus device

The Al–C–N films are deposited on Si substrates by using a dense plasma focus（DPF） device with aluminum fitted central electrode（anode） and by operating the device with CH_4/N_2 gas admixture ratio of 1：1. XRD results verify the crystalline Al N（111） and Al_3CON（110） phase formation of the films deposited using multiple shots. The elemental compositions as well as chemical states of the deposited Al–C–N films are studied using XPS analysis, which affirm Al–N, C–C, and C–N bonding. The FESEM analysis reveals that the deposited films are composed of nanoparticles and nanoparticle agglomerates. The size of the agglomerates increases at a higher number of focus deposition shots for multiple shot depositions. Nanoindentation results reveal the variation in mechanical properties（nanohardness and elastic modulus）of Al–C–N films deposited with multiple shots. The highest values of nanohardness and elastic modulus are found to be about 11 and 185 GPa, respectively, for the film deposited with 30 focus deposition shots. The mechanical properties of the films deposited using multiple shots are related to the Al content and C–N bonding.

Energy loss of tens keV charged particles traveling in the hot dense carbon plasma

The energy loss of charged particles, including electrons, protons, and α-particles with tens keV initial energy E0, traveling in the hot dense carbon(C) plasma for densities from 2.281 to 22.81 g/cm3 and temperatures from 400 to 1500 eV is systematically and quantitatively studied by using the dimensional continuation method. The behaviors of different charged particles are readily distinguishable from each other. Firstly, because an ion is thousands times heavier than an electron, the penetration distance of the electron is much longer than that of proton and α-particle traveling in the plasma. Secondly, most energy of electron projectile with E0 < 100 keV deposits into the electron species of C plasma, while for the cases of proton and α-particle with E0 < 100 keV,about more than half energy transfers into the ion species of C plasma. A simple decreasing law of the penetration distance as a function of the plasma density is fitted, and different behaviors of each projectile particle can be clearly found from the fitted data.We believe that with the advanced progress of the present experimental technology, the findings shown here could be confirmed in ion-stopping experiments in the near future.

Time-Dependent Cylindrical and Spherical Solitary Structures and Double Layers of Dust Ion-Acoustic Waves in Ultra-Relativistic Dense Plasma

Cylindrical and spherical (nonplanar) solitary waves (SWs) and double layers (DLs) in a multi-ion plasma system (containing inertial positively as well as negatively charged ions, non-inertial degenerate electrons, and negatively charged static dust) are studied by employing the standard reductive perturbation method. The modified Gardner (MG) equation describing the nonlinear propagation of the dust ion-acoustic (DIA) waves is derived, and its nonplanar SWs and DLs solutions are numerically analyzed. The parametric regimes for the existence of SWs, which are associated with both positive and negative potential, and DLs which are associated with negative potential, are obtained. The basic features of nonplanar DIA SWs, and DLs, which are found to be different from planar ones, are also identified.

Computer Simulation of Two Component Dense Plasma by Molecular Dynamics Method

In the present work two component dense semiclassical plasma of protons and electrons is considered.Microscopic and electrodynamic properties of the plasma by molecular dynamic simulation are investigated.For these purposes semiclassical interparticle potential which takes into account quantum mechanical diffraction and symmetry effects is used.The considered range of density of plasma is n=1022cm^(−3)to n=1024cm^(−3).Fluctuations and dynamic dielectric functions were calculated using velocity autocorrelation functions.

Electron localization enhanced photon absorption for the missing opacity in solar interior

The internal solar structure predicted by the standard solar model disagrees with the helioseismic observations even by utilizing the most updated physical inputs, such as the opacity and element abundances. By increasing the Rosseland mean, the decade-old open problem of the missing opacity can be resolved. Herein, we propose that the continuum electrons in the radiative processes lose phases and coherence as matter waves, giving rise to a phenomenon of transient spatial localization. It not only enhances the continuum opacity but also increases the line widths of the bound-bound transitions. We demonstrate our theoretical formulation by investigating the opacity of solar mixtures in the interior. The Rosseland mean demonstrates an increase of 10%-26% in the range of 0.3 R⊙-0.75 R⊙. The results are compared with the recent experimental data and the existing theoretical models. Our findings provide novel clues to the open problem of the missing opacity in the solar interior and new insight on the radiative opacity in the hot dense-plasma regime.