The purpose of this paper is to calculate proton energy loss straggling using a full conserving dielectric function (FCDF) for plasmas at any degeneracy. This dielectric function takes into account plasma electron-electron collision considering density, momentum, and energy conservation. When only momentum conservation law is accomplished, the FCDF reproduces the well known Mermin dielectric function, when none of the conservations laws are obeyed, the random phase approximation (RPA) is recovered. Then, the FCDF is applied for the first time to the determination of the energy loss straggling. Differences among diverse dielectric functions to determine straggling follow the same behavior for all kind of plasmas then, they do not depend on the plasma degeneracy but essentially do on the value of the collision frequency. These discrepancies can rise up to 5% between FCDF values and the Mermin ones, and 2% between the FCDF ones and RPA ones for plasma with high enough collision frequency. The similarity between FCDF and RPA results is not surprising, as all conservation laws are also considered in RPA dielectric function. The fact that FCDF and RPA give similar results and the fact that FCDF considers electron-electron collisions and RPA does not, means that latter collisions are not significant for energy loss straggling calculations.

The field of diffractive optics is at the same time old and young. Diffraction gratings have been known for two centuries and used extensively in spectroscopy, for example. Also the theoretical understanding of the basic properties of grating diffraction has been well developed since that time. Until the 1960s, the technological foundation of grating manufacture used to be precision mechanics. It was then, when with the advent of the laser, things gradually started to change. On the one hand, laser interferometry became an additional tool to fabricate grating structures with very small periods. On the other hand, many new applications for optics started to develop based on the use of different types of laser sources. Some examples that may be mentioned are—besides modern spectroscopic techniques—areas like material processing, optical communications and information processing, optical data storage, etc. Consequently, the term “diffractive optics” has obtained a different flavor during the past 20–30 years. New types of diffractive elements were being developed with new technologies. This started in the mid-1960s with the invention of computer-generated holography which allowed to create “arbitrary” wavefronts (this means, within practical limits) by diffracting a light wave at an irregular binary structure. The computation and fabrication of computer-generated holograms was made possible by then newly available digital computers and plotting equipment. Since the early 1970s, people started to make diffractive elements using microfabrication techniques (lithography, etching, etc.) adapted from the processing of electronic circuits. These ideas were initially demonstrated in industrial research laboratories like Philips and Thomson-CSF.

After achieving significant research results on laser-driven boron fusion, the essential facts are presented how the classical very low-energy gains of the initially known thermal ignition conditions for fusion of hydrogen (H) with the boron isotope 11 (HB11 fusion) were bridged by nine orders of magnitudes in agreement with experiments. This is possible under extreme non-thermal equilibrium conditions for ignition by >10 PW-ps laser pulses of extreme power and nonlinear conditions. This low-temperature clean and low-cost fusion energy generation is in crucial contrast to local thermal equilibrium conditions with the advantage to avoid the difficulties of the usual problems with extremely high temperatures.

We present a non-relativistic analytic quantum mechanical model to calculate angular differential cross-sections for laser-assisted proton nucleon scattering on a Woods–Saxon optical potential where the nth-order photon absorption is taken into account simultaneously. With this novel description we can integrate two well-established fields, namely low-energy nuclear physics and multi-photon processes together. As a physical example we calculate cross-sections for proton–12C collision at 49 MeV in the laboratory frame in various realistic laser fields. We consider optical Ti:sapphire and X-ray lasers with intensities which are available in existing laser facilities or in the future ELI or X-FEL.

In this paper, the interaction of intense lasers with overdense plasmas is investigated. Based on the modified nonlinear wave equation describing the interaction of intense laser and overdense plasmas in nonparaxial region, due to the influence of off-axis components a2 and a4 in nonparaxial region, we first find the three-splitted laser beam intensity profile, besides, discuss detailed the forming mathematic and some possible physical conditions of the single highly self-focusing beam profile, two-splitted beam, and three-splitted beam profile. In addition, we also investigate the influence of the parameters βE02 and ρ2 on splitted beam profiles.

The effects of the polarized incident laser pulse on the electrons of the plasma surface and on the reflected pulse in the relativistic laser-plasma interaction is investigated. Based on the relativistic oscillating mirror and totally reflecting oscillating mirror (TROM) regimes, the interaction of the intense polarized laser pulses with over-dense plasma is considered. Based on the effect of ponderomotive force on the characteristic of generated electron nano-bunches, considerable increasing in the localization and charges of nano-bunches are realized. It is found that the circularly polarized laser pulse have Ne/Ncr of 1500 which is almost two and seven times more than the amounts for P-polarized and S-polarized, respectively.

A computational analysis is performed to investigate the suppression mechanism of magnetohydrodynamic (MHD) instability. Three different techniques have been considered which allow us to reduce the total growth of the instability: 1. doublecascades liner; 2. linear rotation and 3. externally generated axial magnetic field. Double gas-puff with specifically structured density: massive inner shell and light outer one for a given current shape makes it possible to suppress significantly the MHD instability evolution. Possible mechanism of the instability dumping has been proposed. The load design is being analyzed for the case of liner rotation with initial angular velocity. Different values of the velocities have been considered. The using of an external magnetic field allows us to suppress the instability when the field reaches the specified shape and optimal value. The estimation of the fraction of magnetic energy and energy of rotation in the full energy of the liner is done. The influence of axial field on MHD instability growth is analyzed.

The aim of the presented experiments is to study the transport of a heavy ion beam in a high-current plasma channel. The discharge is initiated in NH3 gas at pressures between 2 and 20 mbar by a line-tuned CO2 laser. A stable discharge over the entire electrode gap (0.5 m) was achieved for currents up to 60 kA. Concerning the ion beam transport, the magnetic field distribution inside the plasma channel has to be known. The ion-optical properties of the plasma channel have been investigated using different species of heavy ions (C, Ni, Au, U) with 11.4 MeV/u during six runs at the Gesellschaft für Schwerionenforschungs-UNILAC linear accelerator. The high magnetic field allowed the accomplishment of one complete betatron oscillation along the discharge channel. The results obtained up to now are very promising and suggest that, by scaling the discharge gap to longer distances, the beam transport over several meters is possible with negligible losses.

The effect of multiple ionization on Kα spectra is investigated for aluminum targets irradiated by intense lithium beams. Multiple ionization cross sections have been calculated using a formulation incorporating single-electron ionization probability in the binomial distribution. In contrast to conventional binary-encounter approximation (BEA) theory, the single-electron ionization probabilities for each atomic shell have been calculated using a combination of modified plane-wave Born approximation (MPWBA) and an empirical effective interaction radius which is dependent on both the target ion and the projectile. Our calculations show that the effect of multiple inner-shell ionization on aluminum Kα spectra observed in intense lithium beam experiments is important. Multiple ionization effects become less important as the target ionization state increases. Nevertheless, even for highly ionized species up through Be-like Al multiple ionization effects can be significant and must be considered in the analysis of spectra obtained in intense Li beam-plasma interaction experiments.

An experimental analysis is conducted to visualize sidescattered second harmonic spectra originating from the critical surface of a plasma produced from a 1, 064-nm laser beam. It is shown that longitudinal and transverse wave-scattering mechanisms producing the second harmonic may also alter the local plasma parameters. These irregular plasma parameter variations and the perturbed spatial uniformity of the incident laser beam can, in turn, be visualized through the second harmonic behavior. This work confirms the origin of the second harmonic production in an inhomogeneous plasma. Time evolution of the optical density of this harmonic showed spectral shifts due to the Doppler effect related to the critical surface dynamics. On the time-integrated spectra, shifted secondary peaks have been observed, indicating that the second harmonic takes its origin also from parametric decay as well as electron decay instability. Other properties of the interaction physics are deduced from the present second harmonic study.

The interaction of the mixing zone between two gases of different densities with compression waves and shock waves has been investigated. The characteristics of the mixing zone in which the Rayleigh–Taylor instability is developing have been analyzed. The evolution of the mixing zone volume and mass during the accelerated motion has been defined. A qualitative distinction in the evolution of the mixing zone under the influence of a continuous deceleration resulting from the interaction with the reflected compression wave—shockless deceleration—is revealed as compared to deceleration that is accompanied by appearance of a shock wave moving through the mixing zone—shock-induced deceleration.

At the frontier of plasma physics and technology are applications of laser-generated plasmas to laboratory simulations of astrophysical phenomena and to industrial processing. This article presents work at the Naval Research Laboratory in both of these areas. We show how laser plasmas are used to measure a blast wave corrugation overstability important in astrophysics. Detailed atomic physics calculations of radiative cooling within the blast front are used to develop a criterion of the existence of the overstability and are used to explain the experimental results. The criterion depends on quantities such as element abundances, densities, temperatures, and blast wave velocities—quantities which can be measured spectroscopically—and therefore used to infer whether astrophysical blast wave nonuniformities are the result of this instability. In other experiments, high-velocity jets are formed in the laboratory using miniature hollow cones. Jets produced by these cones are used to study the physics of jets occurring in supernovae and in star-forming accretion disks. In industrial semiconductor processing, annealing, that is, removing crystal damage and electrically activating the semiconductor, is a critical step. Industrial annealing techniques most often utilize heat generated by an oven, flash lamps, or a low-power laser. During such heating dopants within the semiconductor lattice diffuse and spread. This degrades the performance of circuits in which the individual circuit elements are very close to each other. We are developing an annealing technique in which shock or sound waves generated by a laser plasma are used to anneal the semiconductor. We have demonstrated that the method works over small areas and that it does not lead to significant dopant diffusion.

A new electro-optical technique has been developed in which a streak camera is coupled to a Pockels cell with a fast risetime. This technique can improve the time resolution of the high voltages observed in laser produced plasmas between one and two orders of magnitude in comparison to the best oscilloscope measurements. This method should prove useful in confirming the existence of electrostatic fields and elucidating the structure of the wave instabilities found in laser produced plasmas.

The new possibility of side-on laser ignition of p-11B with negligible radioactivity encouraged to study the fusion of solid state p-7Li fuel that again turns out to be only about 10 times more difficult than the side-on ignition of solid deuterium-tritium using petawatt-picosecond laser pulses at anomalous interaction conditions if very high contrast ratio. Updated cross sections of the nuclear reaction are included.

One-dimensional particle-in-cell and Monte-Carlo (FLUKA) simulation methods were used together, in order to investigate the production of positrons in lead targets, illuminated by a short-pulse high-intensity laser. The study is focused on lead targets of 1 mm thickness and more and pulses of intensity in the range 1019–1022 W/cm2. The calculations provided an estimate of an absolute number of positrons and the ratio of electrons and positrons emerging from the target. The thickness of the target is scaled in order to find an optimal thickness that could provide a neutral electron-positron beam.

Recent heavy ion fusion target studies show that it is possible to achieve ignition with direct drive and energy gain larger than 100 at 1 MJ. To realize these advanced, high-gain schemes based on direct drive, it is necessary to develop a reliable beam smoothing technique to mitigate instabilities and facilitate uniform deposition on the target. The dynamics of the beam centroid can be explored as a possible beam smoothing technique to achieve a uniform illumination over a suitably chosen region of the target. The basic idea of this technique is to induce an oscillatory motion of the centroid for each transverse slice of the beam in such a way that the centroids of different slices strike different locations on the target. The centroid dynamics is controlled by a set of biased electrical plates called “wobblers.” Using a model based on moments of the Vlasov-Maxwell equations, we show that the wobbler deflection force acts only on the centroid motion, and that the envelope dynamics are independent of the wobbler fields. If the conducting wall is far away from the beam, then the envelope dynamics and centroid dynamics are completely decoupled. This is a preferred situation for the beam wobbling technique, because the wobbler system can be designed to generate the desired centroid motion on the target without considering its effects on the envelope and emittance. A conceptual design of the wobbler system for a heavy ion fusion driver is briefly summarized.

This paper is reviewing the amplification of XUV radiation at 519.7 and 498.5 Å with a gain-length product of 2.5 and 2.2 for the 4f-3d and 4d-3p transition in an oxygen Z-pinch plasma. Time resolved measurements of the O VI (519.7 Å) transition were performed and the dependence of the line intensity on the discharge current and initial gas pressure is reported.

In this paper, we present the results of studies on ion emission characteristics of a laser plasma produced from a copper nano-particle layer of 1–3 µm thickness coated over polished surface of a solid copper target. Laser intensity of 1013–1014 W/cm2 was produced on the targets by a 2 J Nd:glass laser having a variable pulse duration of 300–800 ps. Nano-particle size was in the range of 15–25 nm. Ion emission from the nano-particle plasma was compared with plasma generated from a polished copper target. Ion emission from the nano-structured target was observed to depend on the polarization of the incident laser beam. This effect was stronger for a shorter laser pulse. X-ray emission was measured in the soft and hard X-ray region (0.7 to 8 keV) using various X-ray filters. A nano-particle coated target is found to yield a larger flux as well as velocity of ions as compared to polished target when the laser polarization is parallel to the plane containing target normal and detector axis. However, no X-ray enhancement has been observed in the wavelength range 1.5 to 20 Å.

Heavy-ion accelerators can provide various beams from protons to uranium ions with energies ranging from a few keV/u to more than 1 GeV/u. The Munich Tandem van de Graaff accelerator has been used for most of the experiments described in this article. It can provide continuous or pulsed beams of almost all elements with particle energies of about 3.5 MeV/u. The pulse width is typically 2 ns. Maximum DC-beam currents of the order of 10 μA can be obtained, for example, for 32S ions. When the beam is focused to a beam spot of about 3 mm diameter, the flux of the ions is comparable to the flux of fission fragments used for nuclear-pumped lasers. Ion beam pumping is therefore well suited for model experiments of nuclear-pumped lasers. Technical aspects of ion beam-pumped lasers are discussed and the results of the lasers that have thus far been pumped by this method aresummarized. As ion beams are available either continuous or at high-pulse repetition rates ranging from tens of kHz to MHz, detailed spectroscopic and time-resolved studies of the emission of light induced by heavy-ion excitation of the target material can easily be performed. Experiments in which the emission by rare gas excimers and line radiation from atoms and ions has been studied are described. Lifetime measurements of excited levels at different target densities were used to measure collisional rate constants.

Terahertz (THz) radiation generation by nonlinear mixing of two laser beams, obliquely incident on an overdense plasma is investigated. In an overdense plasma, the laser beams penetrate to only thin layer of a plasma surface and reflected. At this thin layer, the laser beams exert a ponderomotive force on the electrons of plasma and impart them oscillatory velocity at the different frequency of lasers. THz waves appear in the reflected component from the plasma surface. The amplitude of THz waves can be augmented by applying the magnetic field perpendicular to the direction of propagation of lasers. It is found that the field strength of the emitted THz radiations is sensitive to the angle of incident of the laser beams, beat frequency, and magnetic field strength. In this scheme, the magnetic field strength plays an important role for strong THz wave generation.