Laser Beam Propagation, Filamentation and Channel Formation in Laser-produced Plasmas PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
The understanding of laser beam propagation through underdense plasmas is of vital importance to laser-plasma interaction experiments, as well as being a fundamental physics issue. Formation of plasma channels has numerous applications including table-top x- ray lasers and laser-plasma-produced particle accelerators. The fast ignitor concept, for example, requires the formation of an evacuated channel through a large, underdense plasma. Scaled experiments have shown that the axial extent of a channel formed by a 100 ps pulse is limited by the onset of the filamentation instability. We have obtained quantitative comparison between filamentation theory and experiment. More recent experiments have shown that by increasing the duration of the channel-forming pulse, the filamentation instability is overcome and the channel extent is substantially increased. This result has important implications for the fast ignitor design and the understanding of time-dependent beam dynamics.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
The understanding of laser beam propagation through underdense plasmas is of vital importance to laser-plasma interaction experiments, as well as being a fundamental physics issue. Formation of plasma channels has numerous applications including table-top x- ray lasers and laser-plasma-produced particle accelerators. The fast ignitor concept, for example, requires the formation of an evacuated channel through a large, underdense plasma. Scaled experiments have shown that the axial extent of a channel formed by a 100 ps pulse is limited by the onset of the filamentation instability. We have obtained quantitative comparison between filamentation theory and experiment. More recent experiments have shown that by increasing the duration of the channel-forming pulse, the filamentation instability is overcome and the channel extent is substantially increased. This result has important implications for the fast ignitor design and the understanding of time-dependent beam dynamics.
Author: National Research Council
Publisher: National Academies Press
ISBN: 030908637X
Category : Science
Languages : en
Pages : 177
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Book Description
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.
Author: See Leang Chin
Publisher: Springer Science & Business Media
ISBN: 1441906886
Category : Science
Languages : en
Pages : 138
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Book Description
This book attempts to give a discussion of the physics and current and potential applications of the self-focusing of an intense femtosecond laser pulse in a tra- parent medium. Although self-focusing is an old subject of nonlinear optics, the consequence of self-focusing of intense femtosecond laser pulses is totally new and unexpected. Thus, new phenomena are observed, such as long range lam- tation, intensity clamping, white light laser pulse, self-spatial ltering, self-group phase locking, self-pulse compression, clean nonlinear uorescence, and so on. Long range propagation at high intensity, which is seemingly against the law of diffraction, is probably one of the most exciting consequences of this new sub- eld of nonlinear optics. Because the intensity inside the lament core is high, new ways of doing nonlinear optics inside the lament become possible. We call this lamentation nonlinear optics. We shall describe the generation of pulses at other wavelengths in the visible and ultraviolet (UV) starting from the near infrared pump pulse at 800 nm through four-wave-mixing and third harmonic generation, all in gases. Remotely sensing uorescence from the fragments of chemical and biological agents in all forms, gaseous, aerosol or solid, inside the laments in air is demonstrated in the labo- tory. The results will be shown in the last part of the book. Through analyzing the uorescence of gas molecules inside the lament, an unexpected physical process pertaining to the interaction of synchrotron radiation with molecules is observed.
Author:
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ISBN:
Category :
Languages : en
Pages :
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Author: Albert L. Osterheld
Publisher: American Institute of Physics
ISBN:
Category : Science
Languages : en
Pages : 328
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Book Description
Contains papers based on 30 talks presented at the Tenth American Physical Society Topical Conference on Atomic Processes in Plasmas, held in San Francisco in January 1996. The volume begins with a section on atomic physics in tokamak plasmas, followed by sections covering atomic physics in astrophy
Author: Suyash Bajpai
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
The laser filamentation process in gases and its consequences have been at the center of interest over the three recent decades. The filament wake channel is formed by the laser pulse as a highly nonequilibrium and optically underdense plasma column. The contents of the plasma evolve towards equilibrium, giving rise to various transient optical effects. When filamentation occurs in a dense gas, it leads to the production of the excessively high density of excited atoms as compared to the density of ions. We used a kinetic model of the competing electron-collisional processes in the case of high-pressure argon gas and explored the sensitivity of the resulting excited-to-ionized atoms number density ratio to the envelope shape of the driving laser pulse. Considering three different families of the pulse shapes, we have shown that the ratio of excited atoms to ions in the dense gas can be manipulated and further increased. To further investigate the structure of the plasma column, we studied the filamentation process at the crossing of two laser beams. We have shown that in this case the process is significantly affected by the transient intensity grating caused by the beam interference in the crossing area, which leads to the formation of a microscopically structured filament wake channel. In particular, the grating of excited atom density is formed in the channel. We obtained characteristics of such excitation gratings that are controlled by the spatial and temporal characteristics of the crossing pulses. A nonlinear optical effect that is crucial in the context of excess excited atoms is the Rabi sideband generation. The Rabi sideband patterns from a one-dimensional plasma channel have already been studied. We considered theoretically the probing of the above-mentioned excitation gratings by a picosecond laser beam of 800 nm carrier wavelength and the formation of the characteristic spatial-spectral patterns of the Rabi sidebands. We demonstrated the sensitivity of these Rabi sideband patterns towards the grating characteristics, probe beam shape and wavelength and to the position of the observation screen and the observation slit on the screen. As our capstone work, we explored filamentation of long-wavelength laser pulses in atmospheric-pressure gases, as this situation effectively meets the dense gas criteria. We worked at transforming the theoretical and computational techniques that we developed for high-pressure gases at typical laser wavelengths (~800 nm) to be applicable to atmospheric-pressure gases at longer laser wavelengths (~3900 nm). Intense, ultrashort laser pulses of these latter carrier wavelength values just recently have become available for experiments and carry a great promise for applications in atmospheric optics, atmospheric chemistry, and related disciplines.
Author: Andre D. Bandrauk
Publisher: Springer
ISBN: 3319230840
Category : Science
Languages : en
Pages : 223
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Book Description
This book is focused on the nonlinear theoretical and mathematical problems associated with ultrafast intense laser pulse propagation in gases and in particular, in air. With the aim of understanding the physics of filamentation in gases, solids, the atmosphere, and even biological tissue, specialists in nonlinear optics and filamentation from both physics and mathematics attempt to rigorously derive and analyze relevant non-perturbative models. Modern laser technology allows the generation of ultrafast (few cycle) laser pulses, with intensities exceeding the internal electric field in atoms and molecules (E=5x109 V/cm or intensity I = 3.5 x 1016 Watts/cm2 ). The interaction of such pulses with atoms and molecules leads to new, highly nonlinear nonperturbative regimes, where new physical phenomena, such as High Harmonic Generation (HHG), occur, and from which the shortest (attosecond - the natural time scale of the electron) pulses have been created. One of the major experimental discoveries in this nonlinear nonperturbative regime, Laser Pulse Filamentation, was observed by Mourou and Braun in 1995, as the propagation of pulses over large distances with narrow and intense cones. This observation has led to intensive investigation in physics and applied mathematics of new effects such as self-transformation of these pulses into white light, intensity clamping, and multiple filamentation, as well as to potential applications to wave guide writing, atmospheric remote sensing, lightning guiding, and military long-range weapons. The increasing power of high performance computers and the mathematical modelling and simulation of photonic systems has enabled many new areas of research. With contributions by theorists and mathematicians, supplemented by active experimentalists who are experts in the field of nonlinear laser molecule interaction and propagation, Laser Filamentation sheds new light on scientific and industrial applications of modern lasers.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Paul F. Barbara
Publisher: Springer Science & Business Media
ISBN: 3642803148
Category : Science
Languages : en
Pages : 477
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Book Description
This volume contains papers presented at the Tenth International Conference on Ultrafast Phenomena held at Del Coronado, California, from May 28 to June 1, 1996. The biannual Ultrafast Phenomena Conferences provide a forum for the discussion of the latest advances in ultrafast optics and their applications in science and engineering. The Ultrafast Phenomena Conference maintains a broad international representation with 391 participants from 18 countries, including 94 students attending the conference. The multidisciplinary character of this meeting provides a cross-fertilization of ultrafast concepts and techniques among various scientific and engineering disciplines. The enthusiasm of the paticipants, the originality and quality of the papers that they presented, and the beautiful conference site combined to produce a very successful and enjoyable meeting. Progress was reported in the technology of generating ultrashort pulses, in cluding new techniques for improving laser-pulse duration, output power, wave length range, and compactness. Ultrafast spectroscopy continues to impact on and expand the knowledge base of fundamental processes in physics, chemistry, biol ogy and engineering. In addition ultrafast phenomena now extends to real-world applications in biology, high-speed communication, and material diagnostics. The Tenth Ultrafast Phenomena Conference was highlighted by a 'special event' in which the developments of the previous conferences were reviewed in a panel discussion by G. Mourou, E. Ippen, A. Migus, A. Laubereau and R. Hochstrasser.
Author: Robert W. Boyd
Publisher: Springer Science & Business Media
ISBN: 0387347275
Category : Science
Languages : en
Pages : 611
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Book Description
Self-focusing has been an area of active scientific investigation for nearly 50 years. This book presents a comprehensive treatment of this topic and reviews both theoretical and experimental investigations of self-focusing. This book should be of interest to scientists and engineers working with lasers and their applications. From a practical point of view, self-focusing effects impose a limit on the power that can be transmitted through a material medium. Self-focusing also can reduce the threshold for the occurrence of other nonlinear optical processes. Self-focusing often leads to damage in optical materials and is a limiting factor in the design of high-power laser systems. But it can be harnessed for the design of useful devices such as optical power limiters and switches. At a formal level, the equations for self-focusing are equivalent to those describing Bose-Einstein condensates and certain aspects of plasma physics and hydrodynamics. There is thus a unifying theme between nonlinear optics and these other disciplines. One of the goals of this book is to connect the extensive early literature on self-focusing, filament-ation, self-trapping, and collapse with more recent studies aimed at issues such as self-focusing of fs pulses, white light generation, and the generation of filaments in air with lengths of more than 10 km. It also describes some modern advances in self-focusing theory including the influence of beam nonparaxiality on self-focusing collapse. This book consists of 24 chapters. Among them are three reprinted key landmark articles published earlier. It also contains the first publication of the 1964 paper that describes the first laboratory observation of self-focusing phenomena with photographic evidence.
