Shalom Eliezer

The Interaction of High-Power Lasers With Plasmas

This book deals with the fundamental physics of numerous plasma processes that occur during laser plasma interactions. The subject matter is related to both basic plasma physics and applied physics. The author starts with the essentials of high power lasers whose duration ranges from nanoseconds to femtoseconds, and then builds up an introduction to plasma physics by describing ionization, well known transport coefficients (electrical and thermal conductivities, diffusion, viscosity, energy transport etc), Debye length, plasma oscillations and the properties of the laser induced plasma medium. The book contains plasma dynamical equations for describing the hydrodynamic and kinetic phenomena, and treating particle dynamics by computer simulation. The ponderomotive force is discussed for small amplitude electromagnetic fields in an unmagnetized plasma. However, for intense laser beams one should obtain new expressions for the relativistic ponderomotive force, which are totally absent from this book. Furthermore, in laser plasma interactions strong magnetic fields are produced which will drastically modify the relativistic ponderomotive force expressions. The physics of collisional absorption of electromagnetic waves and their propagation in a nonuniform unmagnetized plasma has been elegantly described. The phenomena of the resonance absorption of laser light is also discussed. Simple models for the parametric processes are developed, while there are no discussions of cavitons/envelope solitons. The latter are usually regarded as possible nonlinear states of the modulational/filamentational instabilities. Rather, the author presents a description of a K-dV equation for nonlinear ion-acoustic waves without the laser field. The description of a non-envelope ion-acoustic soliton has already appeared in many plasma physics textbooks. The book contains a short chapter on the self-similar plasma expansion in vacuum, double layers, and charged particle acceleration. However, the author has not touched on the plasma based high energy charged particle accelerators, which involve short intense laser pulses and which are at the frontier of modern plasma physics. There is a nice chapter dealing with laser induced magnetic fields and waves in magnetized plasmas. The physics and mathematical details of the electron energy transport and heat waves, which are of significant interest in inertial confinement fusion, are described in depth. Comprehensive studies of shock waves and rarefaction waves are presented, and their relevance to high power pulsed laser drivers is discussed. Finally, the author has given a lucid description of hydrodynamic instabilities (i.e. the Rayleigh-Taylor, the Richtmyer-Meshkov, the Kelvin-Helmholtz), which are of great importance in laser-plasma interactions and in astrophysics. It would have been nice if the author would have also included a more physical description of the nonlinear evolution of those instabilities which play a significant role in the formation of fingers, bubbles and vortices in laboratories and in astrophysical settings. The book is well written and will serve as a valuable asset for graduate students and physicists working in the area of laser plasma interactions and high energy astrophysics. It should also be useful for teaching masters level courses on laser plasma interactions. The reviewer highly recommends the book to the interested reader. P K Shukla

Fundamentals of equations of state

A summary of thermodynamics equation of state for an ideal gas law of equipartition of energy and effects of vibrational and rotational motions Bose-Einstein equation of state Fermi-Dirac equation of state ionization equilibrium and the Saha equation Debye-Hnckel equation of state the Thomas-Fermi and related models Grnneisen equation of state an introduction to fluid mechanics in relation to shock waves derivation of hydrodynamics from kinetic theory studies of the equations of state from high-pressure shock waves in solids equation of state and inertial confinement fusion applications of equations of state in astrophysics equations of state in elementary particle physics.

Volume ignition targets for heavy-ion inertial fusion

Inertial confinement fusion (ICF) targets can be imploded by heavy-ion beams (HIBs) in order to obtain a highly compressed fuel microsphere. The hydrodynamic efficiency of the compression can be optimized by tuning the ablation process in order to produce the total evaporation of the pusher material by the end of the implosion. Such pusherless compressions produce very highly compressed targets for relatively short confinement times. However, these times are long enough for a fusion burst to take place, and burnup fractions of 30% and higher can be obtained if the volume ignition requirements are met. Numerical simulations demonstrate that targets of 1-mg DT driven by a few MJ can yield energy gains of over 70. Although direct drive is used in these simulations, the main conclusions about volume ignition are also applicable to indirect drive.

Double layer acceleration by laser radiation

It is shown that it is possible to accelerate micro-foils to velocities from 10 cm/s up to relativistic velocities without the disturbance of the Rayleigh-Taylor instability. The acceleration occurs due to the radiation pressure of proper high power lasers. In these systems, the ablation force is negligible relative to the ponderomotive force that dominates the acceleration. The laser irradiances of 10 W/cm< IL< 10 21 W/cm with a pulse duration of the order of 10 picoseconds can accelerate a micro-foil by the laser radiation pressure to velocities as high as 10 cm/s before breaking by Rayleigh Taylor (RT) instability. Similarly, laser irradiances of IL> 10 21 W/cm with pulse duration of the order of 10 femtoseconds can accelerate a micro-foil to relativistic velocities without RT breaking. Due to the nature of the accelerating ponderomotive force, in both the relativistic and non-relativistic cases, the structure of the accelerated target contains a double layer (DL) at the interface of the laser-target interaction. The DL acts as a piston during the acceleration process. The influence of the DL surface tension on the RT instability is also analyzed in this paper.

Applications of Laser-Plasma Interactions

Inertial Fusion Energy Kunioki Mima, Masakatsu Murakami, Sadao Nakai, and Shalom Eliezer Accelerators James Kogan X-Ray Sources Hiroaki Nishimura X-Ray Lasers Hiroyuki Daido, Tetsuya Kawachi, Kengo Moribayashi, and Alexander Pirozhkov Nuclear and Particle Physics with Ultraintense Lasers Jose Tito Mendonca and Shalom Eliezer Equations of State Shalom Eliezer and Zohar Henis Material Processing with Femtosecond Lasers Masayuki Fujita Nanoparticles Induced by Femtosecond Lasers Shalom Eliezer Index

Influence of hydrogen on microstructure and dynamic strength of lean duplex stainless steel

In this research dynamic strength is analyzed for the first time in a lean duplex stainless steel (LDS) uncharged and charged with hydrogen. In particular, the dynamic yield stress (Hugoniot elastic limit, HEL) and the dynamic tensile strength (spall strength) of LDS are studied. We also investigate the deformation mechanism of the LDS using metallurgical analysis. LDS was chosen since it has a mixed structure of ferrite (BCC, α) and austenite (FCC, γ), which allows an attractive combination of high strength and ductility. The dynamic loading was produced by accelerating an LDS impactor in a gas gun into an LDS target (uniaxial plate impact experiments). Data collection was performed by optical diagnostics through the velocity interferometer for any reflector device. The impact produces conditions of high pressure and high strain rate (~105xa0s−1), which can be comparable to explosions during extreme conditions of failure. In addition, investigations of hydrogen interaction with both crystal lattices were performed by means of X-ray diffraction (XRD) measurements. Several assessments can be made based on the results of this study. Using XRD analysis, it will be shown that even after hydrogen desorption some hydrogen remained trapped in the austenitic phase causing a small lattice expansion. After impact, a brittle spall was seen, which occurred through cavitation of cracks along both phases’ grain boundaries. Hydrogen increases the dynamic yield strength and when hydrogen content is sufficiently high it will also lead to higher spall strength. The relation between microstructure and dynamic strength of the LDS in the presence of hydrogen is discussed in detail.

Topography retrieval using different solutions of the transport intensity equation

The topography of a phase plate is recovered from the phase reconstruction by solving the transport intensity equation (TIE). The TIE is solved using two different approaches: (a) the classical solution of solving the Poisson differential equation and (b) an algebraic approach with Zernike functions. In this paper we present and compare the topography reconstruction of a phase plate with these solution methods and justify why one solution is preferable over the other.

Core holes, charge disorder, and transition from metallic to plasma properties in ultrashort pulse irradiation of metals

We study the details of a gradual change in electron properties from those of a nearly-free-electron (NFE) metal to those of a strongly-coupled plasma, in ultrashort pulse energy deposition in solid metal targets. Time scales shorter than those of a target surface layer expansion are considered. Both the case of an optical laser (visible or near infrared wavelengths range) and of a free electron laser (vacuum ultraviolet or X-ray) are treated. The mechanisms responsible for the change in electron behavior are isochoric melting, lattice charge disordering, and electron mean free path reduction. We find that the transition from metal to plasma usually occurs via an intermediate stage of a charge-disordered solid (solid plasma), in which ions are at their lattice sites but the ionization stages of individual ions differ due to ionization from localized bound states. Charge disordered state formation is very rapid (typically, few femtoseconds or few tens of femtoseconds). Pathway to charge-disordered state differs in simple metals and in noble metals. Probabilities are derived for electron impact ionization and 3-body recombination of a bound ionic state in solid-density medium, applicable both in metal and in plasma regime. An evolution of energy coupling between electron and ion subsystems, from metallic electron-phonon (e-ph) to plasma electron-ion (e-i) coupling, is considered. Substantial increase in coupling parameter is expected as a result of charge disorder.

Inertial fusion features in degenerate plasmas

Very high plasma densities can be obtained at the end of the implosion phase in inertial fusion targets, particularly in the so-called fast-ignition scheme ( Tabak et al. , 1994 ; Mulser & Bauer, 2004 ), where a central hot spark is not needed at all. By properly tailoring the fuel compression stage, degenerate states can be reached ( Azechi et al. , 1991 ; Nakai et al. , 1991 ; McCory, 1998 ). In that case, most of the relevant energy transfer mechanisms involving electrons are affected ( Honrubia & Tikhonchuk, 2004 ; Bibi & Matte, 2004 ; Bibi et al. , 2004 ). For instance, bremsstrahlung emission is highly suppressed ( Eliezer et al. , 2003 ). In fact, a low ignition-temperature regime appears at very high plasma densities, due to radiation leakage reduction ( Leon et al. , 2001 ). Stopping power and ion-electron coulomb collisions are also changed in this case, which are important mechanisms to trigger ignition by the incoming fast jet, and to launch the fusion wave from the igniting region into the colder, degenerate plasma. All these points are reviewed in this paper. Although degenerate states would not be easy to obtain by target implosion, they present a very interesting upper limit that deserves more attention in order to complete the understanding on the different domains for inertial confinement fusion.

Petawatt laser pulses for proton-boron high gain fusion with avalanche reactions excluding problems of nuclear radiation

An alternative way may be possible for igniting solid density hydrogen-11B (HB11) fuel. The use of >petawatt-ps laser pulses from the non-thermal ignition based on ultrahigh acceleration of plasma blocks by the nonlinear (ponderomotive) force, has to be combined with the measured ultrahigh magnetic fields in the 10 kilotesla range for cylindrical trapping. The evaluation of measured alpha particles from HB11 reactions arrives at the conclusion that apart from the usual binary nuclear reactions, secondary reactions by an avalanche multiplication may cause the high gains, even much higher than from deuterium tritium fusion. This may be leading to a concept of clean economic power generation.