Download or read book Parametric Instabilities in Laser written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this LDRD was the study of parametric instabilities on a laser-produced plasma, addressing crucial issues affecting the coupling between the laser and the plasma. We have made very good progress during these three years, in advancing our understanding in many different fronts. Progress was made in both theoretical and experimental areas. The coupling of high-power laser light to a plasma through scattering instabilities is still one of the most complex processes in laser-plasma interaction physics. In spite of the relevance of these parametric processes to inertial confinement fusion (ICF) and all other situations where a high-power laser beam couples to a plasma, many aspects of the interaction remain unexplained, even after many years of intensive experimental and theoretical efforts. Important instabilities under study are stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and the Langmuir decay instability (LDI). The study of these instabilities is further complicated by the competition and interplay between them, and, in the case of ICF, by the presence of multiple overlapping interaction beams. Stimulated Brillouin scattering consists of the decay of the incident electromagnetic (EM) wave into a scattered EM wave and an ion acoustic wave (IAW). Similarly, SRS consists of the decay of the incident EM wave into a scattered EM wave and an electron plasma wave (EPW). Langmuir decay instability is the further decay of an EPW into a secondary EPW and an IAW. The principal areas of research covered during this three-year period were the following: a) Modeling of Parametric Instabilities in Speckles b) Langmuir Decay Instability c) Non Maxwellian Plasmas d) Multiple Interaction Beams e) SBS from Speckle Distributions.
Download or read book Study of Parametric and Hydrodynamic Instabilities in Laser Produced Plasmas written by Shelly Nuruzzaman and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Parametric Instabilities in Femtosecond Laser Produced Plasmas written by Laszlo Veisz and published by . This book was released on 2008-04-01 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-produced plasmas play an important role in plasma physics and fusion research. Parametric instabilities are the most important processes governing the laser-plasma interaction. Some parametric instabilities as two-plasmon decay or stimulated Raman scattering were investigated in this work using an optical signal, the so called 3/2 harmonics. As this harmonic originates from the plasma its characteristics provide important information about the plasma properties. The angular, spectral and temporal structure of this 3/2 harmonics were studied. Detailed theoretical analysis was made based on a new model to explain the measured results and to gain information about the generation process and the plasma.
Download or read book STUDY OF PARAMETRIC INSTABILITIES IN LASER PRODUCED PLASMAS written by MAHMOUD KOTB GAD HAMED and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Laser Plasma Interactions written by Pierre Michel and published by Springer Nature. This book was released on 2023-04-18 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a comprehensive introduction to the physics of laser-plasma interactions (LPI), based on a graduate course taught by the author. The emphasis is on high-energy-density physics (HEDP) and inertial confinement fusion (ICF), with a comprehensive description of the propagation, absorption, nonlinear effects and parametric instabilities of high energy lasers in plasmas. The recent demonstration of a burning plasma on the verge of nuclear fusion ignition at the National Ignition Facility in Livermore, California, has marked the beginning of a new era of ICF and fusion research. These new developments make LPI more relevant than ever, and the resulting influx of new scientists necessitates new pedagogical material on the subject. In contrast to the classical textbooks on LPI, this book provides a complete description of all wave-coupling instabilities in unmagnetized plasmas in the kinetic as well as fluid pictures, and includes a comprehensive description of the optical smoothing techniques used on high-power lasers and their impact on laser-plasma instabilities. It summarizes all the key developments from the 1970s to the present day in view of the current state of LPI and ICF research; it provides a derivation of the key LPI metrics and formulas from first principles, and connects the theory to experimental observables. With exercises and plenty of illustrations, this book is ideal as a textbook for a course on laser-plasma interactions or as a supplementary text for graduate introductory plasma physics course. Students and researchers will also find it to be an invaluable reference and self-study resource.
Download or read book Parametric Instabilities in U V Laser produced Plasmas written by Kazuo A. Tanaka and published by . This book was released on 1982 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parametric Instabilities in Large Nonuniform Laser Plasmas written by and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of parametric instabilities in laser plasmas is of vital importance for inertial confinement fusion (ICF). The long scale-length plasma encountered in the corona of an ICF target provides ideal conditions for the growth of instabilities such as stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and filamentation. These instabilities can have detrimental effects in ICF and their characterization and understanding is of importance. Scattering instabilities are driven through a feedback loop by which the beating between the electromagnetic EM fields of the laser and the scattered light matches the frequency of a local longitudinal mode of the plasma. Any process which interferes with the coherence of this mechanism can substantially alter the behavior of the instability. Of particular interest is the study of laser beam smoothing techniques on parametric instabilities. These techniques are used to improve irradiation uniformity which can suppress hydrodynamic instabilities. Laser beam smoothing techniques have the potential to control the scattering level from parametric instabilities since they provide not only a smoother laser intensity distribution, but also reduced coherence. Beam smoothing techniques that affect the growth of parametric instabilities include spatial smoothing and temporal smoothing by laser bandwidth. Spatial smoothing modifies the phase fronts and temporal distribution of intensities in the focal volume. The transverse intensity spectrum is shifted towards higher spatial wavenumber and can significantly limit the growth of filamentation. Temporal smoothing reduces the coherence time and consequently limits the growth time. Laser bandwidth is required for most smoothing techniques, and can have an independent effect on the instabilities as well.
Download or read book Investigation of Parametric Instabilities in Femtosecond Laser produced Plasmas written by László Veisz and published by . This book was released on 2003 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrodynamic and Parametric Instabilities in a Long Scalelength Laser Produced Plasma written by and published by . This book was released on 1992 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parametric Instabilities in Picosecond Time Scales written by and published by . This book was released on 1993 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coupling of intense laser light with plasmas is a rich field of plasma physics, with many applications. Among these are inertial confinement fusion (ICF), x-ray lasers, particle acceleration, and x-ray sources. Parametric instabilities have been studied for many years because of their importance to ICF; with laser pulses with duration of approximately a nanosecond, and laser intensities in the range 1014--1015W/cm2 these instabilities are of crucial concern because of a number of detrimental effects. Although the laser pulse duration of interest for these studies are relatively long, it has been evident in the past years that to reach an understanding of these instabilities requires their characterization and analysis in picosecond time scales. At the laser intensities of interest, the growth rate for stimulated Brillouin scattering (SBS) is of the order of picoseconds, and of an order of magnitude shorter for stimulated Raman scattering (SRS). In this paper the authors discuss SBS and SRS in the context of their evolution in picosecond time scales. They describe the fundamental concepts associated with their growth and saturation, and recent work on the nonlinear treatment required for the modeling of these instabilities at high laser intensities.
Download or read book Frontiers in High Energy Density Physics written by National Research Council and published by National Academies Press. This book was released on 2003-05-11 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent scientific and technical advances have made it possible to create matter in the laboratory under conditions relevant to astrophysical systems such as supernovae and black holes. These advances will also benefit inertial confinement fusion research and the nation's nuclear weapon's program. The report describes the major research facilities on which such high energy density conditions can be achieved and lists a number of key scientific questions about high energy density physics that can be addressed by this research. Several recommendations are presented that would facilitate the development of a comprehensive strategy for realizing these research opportunities.
Download or read book The Study of Parametric Instabilities in NIF scale Plasmas on Nova written by and published by . This book was released on 1994 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Power Laser Plasma Interaction written by C. S. Liu and published by Cambridge University Press. This book was released on 2019-05-23 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of high-power laser-plasma interaction has grown in the last few decades, with applications ranging from laser-driven fusion and laser acceleration of charged particles to laser ablation of materials. This comprehensive text covers fundamental concepts including electromagnetics and electrostatic waves, parameter instabilities, laser driven fusion,charged particle acceleration and gamma rays. Two important techniques of laser proton interactions including target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA) are discussed in detail, along with their applications in the field of medicine. An analytical framework is developed for laser beat-wave and wakefield excitation of plasma waves and subsequent acceleration of electrons. The book covers parametric oscillator model and studies the coupling of laser light with collective modes.
Download or read book Extending the Validity Range of the Linear Fluid Description of Parametric Instabilities in Laser Produced Plasma written by A. C. Machacek and published by . This book was released on 2000 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self Smoothing of Laser Light in Plasmas written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The modification of the optical characteristics of a laser beam by a plasma is a key issue in laser-plasma coupling. it is critical to understand how this takes place, if we are ever to understand the interaction processes in the plasma corona as well as the coupling at super-high intensities--as when laser pulses approach Petawatt intensities. Interpreting and understanding parametric instabilities in laser-produced plasmas has been a problem of increasing complexity. Improvements in diagnostic capabilities in experimental studies, as well as refinements in the modeling (using different numerical techniques), are showing a complex scenario: strong interplay among instabilities, modification of the plasma conditions caused by the instabilities, and modification to the initial distribution of laser intensity inside the plasma. Of particular interest are stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS), instabilities which have been studied extensively during the past 20 years, both theoretically and experimentally. Until now, most studies--mainly driven by requirements associated with inertial confinement fusion (ICF)--have concentrated on backscattering instabilities. The role of forward instabilities has not received much attention, despite having the potentials for strongly modifying the overall laser-plasma interaction region. The objective of this project is to study numerically the nonlinear enhancement of large-angle, forward scattering of two identical laser beams propagating in a preformed plasma. it is known that filamentation instability and self-focusing are capable of modifying laser-beam geometry, altering the electromagnetic-field distribution and spectral properties. These instabilities, combined with forward SBS, apparently cause a plasma-induced smoothing (self-smoothing) of the laser light as it propagates through the plasma. The final effect may have consequences similar to the temporal smoothing introduced intentionally in many laser systems. They do not propose this phenomenon as a smoothing technique; however, they claim that the understanding of this effect is crucial to the interpretation of experimental results on parametric instabilities.
Download or read book Study of Laser Plasma Interactions Using an Eulerian Vlasov Code written by David J. Strozzi and published by . This book was released on 2004 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a one-dimensional Eulerian Vlasov code for performing kinetic simulations of laser-plasma interactions. We use the code to study parametric instabilities, in particular stimulated Raman scattering. For conditions similar to those of single-hot-spot experiments, we find that kinetic effects are important in the saturation of this instability. Work is underway to make the code to 1 1/2 and 2D (resolving y and py) and parallelize it.
Download or read book Advances in Laser Produced Plasmas Research written by Maricel Agop and published by MDPI. This book was released on 2021-01-21 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world of laser matter interaction has known great and rapid advancements in the last few years, with a considerable increase in the number of both experimental and theoretical studies. The classical paradigm used to describe the dynamics of laser produced plasmas has been challenged by new peculiar phenomena observed experimentally, like plasma particles’ oscillations, plume splitting and self-structuring behavior during the expansion of the ejected particles. The use of multiple complementary techniques has become a requirement nowadays, as different aspects can be showcased by specific experimental approaches. To balance these non-linear effects and still remain tributary to the classical theoretical, views on laser produced plasma dynamics novel theoretical models that cover the two sides of the ablation plasma (differentiability and non-differentiability) still need to be developed. Plasma is a strongly nonlinear dynamic system, with many degrees of freedom and other symmetries, favorable for the development of ordered structures, instabilities and transitions (from ordered to chaotic states). In such contexts, we showcased research based on global and local symmetries, complexity and invariance. This special number highlighted exciting new phenomena related to laser produced plasma dynamics with the implementation of theoretical models, towards understanding the complex reality of laser matter interaction.
