Debye-Length Discrimination of Nonlinear Laser Forces Acting on Electrons in Tenuous Plasmas

Boreham, B. W.; Hora, Heinrich

doi:10.1103/physrevlett.42.776

Cited by 68 publications

(31 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A direct proof of this is the linear dependence of the fast ion energies on the charge number (which is not explainable by thermokinetics or "hot" electrons), these ions being generated in most cases after ponderomotive self-focusing (Hora 1969b) and the generation of the caviton which was discovered numerically on the basis of the preceding theory (Hora 1969b) by Shearer et al (1970). This caviton generation in numerous experiments was clear evidence of the nonlinear force [see chapter 10 of Hora (1991)], although a direct action has been demonstrated by other experiments (Boreham & Hora 1979;Boreham & Luther-Davies 1979;Baldwin & Boreham 1981).…”

Section: Introductionmentioning

confidence: 85%

Beam smoothing and temporal effects:Optimized preparation of laser beams for direct-drive inertial confinement fusion

et al. 1997

Self Cite

View full text Add to dashboard Cite

Direct-drive laser fusion received a number of setbacks from the experimental observation in the 1960s and 1970s of very complex interactions in laser plasma experiments caused by a number of nonlinear and anomalous phenomena. Although smoothing methods were introduced intuitively or empirically-succeeding in reducing these difficulties -it was not until a few years ago that the 20-ps stochastic pulsation mechanism was discovered. We assume here that this 20-ps stochastic pulsation may be the major obstacle to achieving direct-drive fusion, even though it is now generally assumed that the major challenge to the achievement of direct-drive fusion is the Rayleigh-Taylor instability. While we do not discount the importance of the Rayleigh-Taylor mechanisms, we concentrate here on the analysis of the pulsation process. A method of analysis was developed, using time-dependent real-time computations employing a genuine two-fluid model, which includes the interior electric fields and the very large amplitude longitudinal plasma oscillations that are driven by the laser field. These mechanisms, which were first suggested in 1974, reveal themselves now as self-generated von-Laue gratings, preventing the propagation of laser radiation through the outermost plasma corona and preventing energy deposition by temporal interruption caused by thermal relaxation and the subsequent reestablishment of these gratings, and so on. The abolition of this pulsation by broad-band laser irradiation or other smoothing methods is now well understood. A synopsis of these developments is presented here, consistent with Rubbia's proposition of using the MJ drivers for laser fusion, the technology for which is now available.

show abstract

Section: Introductionmentioning

confidence: 85%

Beam smoothing and temporal effects:Optimized preparation of laser beams for direct-drive inertial confinement fusion

et al. 1997

Self Cite

View full text Add to dashboard Cite

show abstract

“…One has to realiZe that this result was enforced from our studies of the radial emission of electrons in vacuum (or very low density plasma with a Debye length larger than the diameter of the laser beam) [14] where the electrons are accelerated by the nonlinear force to 100 eVor 1 keY energy at neodymium glass laser intensities of 1015 0r 1016W/cm2respectively (experiments by Boreham and Luther-Davies [14] [294]). This was very easily understood from the ponderomotive part of the nonlinear force from the radial action of the gradient of the decaying square of the electric field where then according to Eq.…”

Section: Exact Gaussian Beam Cluster Injection Laser Amplifier and mentioning

confidence: 99%

“…Having shown how the Boreham experiment (14) led to the exact derivation of the longitudinal field component of laser beams and to the principle of high accuracy for nonlinear physics, there were importaI\t applications of this experiment. One was the first possib1l1ty to measure the tunnel ionization of helium atoms (Baldwin et al1981) confirming the theory of Keldysh (196) immediately expressing the multiphoton ionization process.…”

Section: Exact Gaussian Beam Cluster Injection Laser Amplifier and mentioning

confidence: 99%

Plasmas at High Temperature and Density

Hora¹

1991

Lecture Notes in Physics Monographs

View full text Add to dashboard Cite

Preface"New physics" is an appealing new keyword, not yet devalued by the ravages of inflation. But what has this to do with such an ugly field as plasma physics, steeped in classical physics, mostly outworn, with all its unsolved and ambiguous technological problems and its messy and open ended numerical studies?"New physics" is concerned with quarks, Higgs particles, grand unified theory, superstrings, gravitational waves, and the profound basics of cosmology and black holes. It is the field of astonishing quantum effects, demonstrated by the von Klitzing effect and hightemperature superconductors. But what can plasma physicists offer, after so many years of expensive and frustrating research to solve the problem of fusion energy?One may suggest that the fascinating research of chaos with applications to plasma, or the achievements of statistical mechanics applied to plasmas, has something to offer and should be the subject of attention. However, this is not the aim of this book.Complementing the traditional aim of physics, which is to interpret the phenomena of nature by generalizing laws such that exact predictions about new properties and effects can be drawn, this book demonstrates how new physics has been derived over the last 30 years from the state of matter which exists at high temperatures (plasma). The advent of the laser, with its very high energy densities and its concentration to extremely small volumes and to very short time periods, opened up a whole new regime for the interaction of materials and high-density plasmas, which enforced the appearance of the "rather new physics".Here are a few examples:• Who would have expected that optical waves in vacuum have a longitudinal component? Thomas Young discovered in 1801 the pure transversality of optical radiation. This was not understandable at that time, when it was known that mechanical waves never exist without longitudinal components. Maxwell's equation then only revealed solutions of the purely transverse plane waves in electromagnetism. Against all this traditional knowledge, the recent findings about the dynamics of electrons driven by laser beams by nonlinear forces led to thẽ xact derivation of longitudinal optical wave components.• The same nonlinear force interaction, in view of momentum transfer in experiments, led to the clarification of the angular momentum ofoptical beams and brought about the first substantiation of the photon spin by a macroscopic property.• The conditions of very high laser intensities led to nonlinear and relativistic generalization of the optical response (dielectrics and absorption) with a prediction of relativistic self-focusing to understand how GeV ions are produced by laser irradiation of solid targets.• The quantum generalization of Coulomb collisions in plasmas at high temperatures explains the anomalous resistivity, in agreement with observations where links are given between the simply derived Coulomb collision frequency and quantum electrodynamics, including stimulated emission. IX that after the first l...

show abstract

“…4 Hora and colleagues have also reviewed and contributed to the development of laser field models and their application to electrodynamics-the accuracy principle. 2,[5][6][7] The importance of the physical model of focused laser fields has been clearly demonstrated in direct laserelectron scattering 5,[8][9][10][11][12][13] and must be considered to accurately model any high-intensity experiment. 14 In this Letter we derive an exact analytical series solution to the full Maxwell wave equation for a laser having a flattened Gaussian transverse profile in the focal plane by using the angular spectrum method.…”

mentioning

confidence: 99%

Exact analytical solution for the vector electromagnetic field of Gaussian, flattened Gaussian, and annular Gaussian laser modes

Sepke¹,

Umstadter²

2006

Opt. Lett.

View full text Add to dashboard Cite

Debye-Length Discrimination of Nonlinear Laser Forces Acting on Electrons in Tenuous Plasmas

Cited by 68 publications

References 7 publications

Beam smoothing and temporal effects:Optimized preparation of laser beams for direct-drive inertial confinement fusion

Beam smoothing and temporal effects:Optimized preparation of laser beams for direct-drive inertial confinement fusion

Plasmas at High Temperature and Density

Exact analytical solution for the vector electromagnetic field of Gaussian, flattened Gaussian, and annular Gaussian laser modes

Contact Info

Product

Resources

About