Download or read book Thomson Scattering from Laser Plasmas written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thomson scattering has recently been introduced as a fundamental diagnostic of plasma conditions and basic physical processes in dense, inertial confinement fusion plasmas. Experiments at the Nova laser facility [E.M. Campbell et al., Laser Part. Beams 9, 209 (1991)] have demonstrated accurate temporally and spatially resolved characterization of densities, electron temperatures, and average ionization levels by simultaneously observing Thomson scattered light from ion acoustic and electron plasma (Langmuir) fluctuations. In addition, observations of fast and slow ion acous- tic waves in two-ion species plasmas have also allowed an independent measurement of the ion temperature. These results have motivated the application of Thomson scattering in closed-geometry inertial confinement fusion hohlraums to benchmark integrated radiation-hydrodynamic modeling of fusion plasmas. For this purpose a high energy 4[omega] probe laser was implemented recently allowing ultraviolet Thomson scattering at various locations in high-density gas-filled hohlraum plasmas. In partic- ular, the observation of steep electron temperature gradients indicates that electron thermal transport is inhibited in these gas-filled hohlraums. Hydrodynamic calcula- tions which include an exact treatment of large-scale magnetic fields are in agreement with these findings. Moreover, the Thomson scattering data clearly indicate axial stagnation in these hohlraums by showing a fast rise of the ion temperature. Its timing is in good agreement with calculations indicating that the stagnating plasma will not deteriorate the implosion of the fusion capsules in ignition experiments.
Download or read book Characterization of High Temperature Laser Produced Plasmas Using Thomson Scattering written by S. Ross and published by . This book was released on 2005 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultraviolet Thomson scattering has been fielded at the Omega Laser Facility to achieve accurate measurements of the plasma conditions in laser-produced high-temperature plasmas. Recent applications to hohlraum targets that have been filled with CH gas or SiO{sub 2} foams have demonstrated a new high temperature plasma regime of importance to laser-plasma interaction studies in a strongly damped regime such as those occurring in indirect drive inertial confinement fusion experiments. The Thomson scattering spectra show the collective ion acoustic features that fit the theory for two ion species plasmas and from which we infer the electron and ion temperature. We find that the electron temperature scales from 2-4 keV when increasing the heater beam energy into the hohlraum from 8-17 kJ, respectively. Simultaneous measurements of the stimulated Raman scattering from a green 527 nm interaction beam show that the reflectivity decreases from 20% to 1% indicating that this instability is strongly damped at high temperatures. These findings support green laser beams as possible driver option for laser-driven fusion experiments.
Download or read book Nonlinear Thomson Scattering of Intense Laser Pulse from Beams and Plasmas written by and published by . This book was released on 1993 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Comprehensive theory is developed to describe the nonlinear Thomson scattering of intense laser fields from beams and plasmas. This theory is valid for linearly or circularly polarized incident laser fields of arbitrary intensities and for electrons of arbitrary energies. Explicit expressions for the intensity distributions of the scattered radiation are calculated and numerically evaluated. The space-charge electrostatic potential, which is important in high density plasmas and prevents the axial drift of electrons, is included self-consistently. Various properties of the scattered radiation are examined, including the linewidth, angular distribution, and the behavior of the radiation spectra at ultrahigh intensities. Non-ideal effects, such as electron energy spread and beam emittance, are discussed. A laser synchrotron source (LSS), based on nonlinear Thomson scattering, may provide a practical method for generating tunable, near monochromatic, well collimated, short pulse x-rays in a compact, relatively inexpensive source. Two examples of possible LSS configurations are presented: an electron beam LSS generating hard (30 keV, 0.4 A) x-rays and a plasma LSS generating soft (0.3 keV, 40 A) x-rays. These LSS configurations are capable of generating ultrashort (approx. 1 ps) x-ray pulses with high peak flux (> 10(21) photons/s) and brightness (> 10(19) photons/s-mm2- mrad (2) 0.1% BW). Synchrotron radiation, Thomson scattering, Laser-plasma interactions.
Download or read book Plasma Scattering of Electromagnetic Radiation written by John Sheffield and published by Academic Press. This book was released on 2010-11-25 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents one of the most powerful methods of plasma diagnosis in exquisite detail, to guide researchers in the theory and measurement techniques of light scattering in plasmas. Light scattering in plasmas is essential in the research and development of fusion energy, environmental solutions, and electronics.Referred to as the "Bible" by researchers, the work encompasses fusion and industrial applications essential in plasma research. It is the only comprehensive resource specific to the plasma scattering technique. It provides a wide-range of experimental examples and discussion of their principles with worked examples to assist researchers in applying the theory. - Computing techniques for solving basic equations helps researchers compare data to the actual experiment - New material on advances on the experimental side, such as the application of high density plasmas of inertial fusion - Worked out examples of the scattering technique for easier comprehension of theory
Download or read book Laser Plasma Interactions written by Dino A. Jaroszynski and published by CRC Press. This book was released on 2009-03-27 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Solid Compendium of Advanced Diagnostic and Simulation ToolsExploring the most exciting and topical areas in this field, Laser-Plasma Interactions focuses on the interaction of intense laser radiation with plasma. After discussing the basic theory of the interaction of intense electromagnetic radiation fields with matter, the book covers three ap
Download or read book The Observation of Enhanced Thomson Scattering in Submicron laser Plasmas written by Steven Howard Batha and published by . This book was released on 1989 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Thomson Scattering from the Free Electrons in a Plasma written by Edward Rolfe and published by . This book was released on 1966 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: A plasma diagnostic technique is presented which utilizes the Thomson scattering of a laser beam from free electrons. By this means a measurement may be made of both electron concentration and temperature. An extensive analysis of background radiation (noise) is given, and of the photoionization effects of the laser beam. Details of a plasma source which continuously simulates conditions in a reentry plasma, of a giant pulse laser, and of detection apparatus are described. By taking advantage of the broad Doppler spectrum of the Thomson-scattered light, measurements of the spectral wings to the exclusion of the laser wavelength permits the elimination of background radiation to a substantial degree. The investigation is specialized to conditions encountered in reentry plasmas, but would be applicable to measurements in rocket exhausts and explosion generated plasmas. (Author).
Download or read book Temperature Determination in X Ray Laser Plasmas by Thomson Scattering written by D. M. Villeneuve and published by . This book was released on 1992 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thomson scattering diagnostics were used to measure electron and ion temperatures in plasmas similar to those used for x-ray lasers. These measurements were compared with predictions of a hydrodynamic simulation. Experimental measurements which can test the accuracy of the codes' predictions can be used to 'calibrate' the codes, and hence lead to either code improvements or an increased confidence in the codes' accuracy. Experiments were performed with plasmas produced from a laser spot focused on solid targets of carbon, germanium and tantalum. The electron temperature could be measured as a function of time at different locations in the plasma, for various laser intensities.
Download or read book Uv Thomson Scattering from X ray Laser Plasmas written by and published by . This book was released on 1991 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Calendar of Oengus written by and published by . This book was released on 1871 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thomson Scattering Techniques in Laser Produced Plasmas written by J. S. Ross and published by . This book was released on 2006 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thomson scattering has been shown to be a valuable technique for measuring the plasma conditions in laser produced plasmas. Measurement techniques are discussed that use the ion-acoustic frequency measured from the collective Thomson-scattering spectrum to extract the electron temperature, ion temperature, plasma flow, and electron density in a laser produced plasma. In a recent study, they demonstrated a novel Thomson-scattering technique to measure the dispersion of ion-acoustic fluctuations that employing multiple color Thomson-scattering diagnostics. They obtained frequency-resolved Thomson-scattering spectra of the two separate thermal ion-acoustic fluctuations with significantly different wave vectors. This new technique allows a simultaneous time resolved local measurement of electron density and temperature. The plasma fluctuations are shown to become dispersive with increasing electron temperature. Furthermore, a Thomson-scattering technique to measure the electron temperature profile is presented where recent experiments have measured a large electron temperature gradient (Te = 1.4 keV to Te = 3.2 keV over 1.5-mm) along the axis of a 2-mm long hohlraum when heated asymmetrically.
Download or read book The Use of Ultraviolet Thomson Scattering as a Versatile Diagnostic for Detailed Measurements of a Collisional Laser Produced Plasma written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Collective Thomson scattering from ion-acoustic waves at 266nm is used to obtain spatially resolved, two-dimensional electron density, sound speed, and radial drift profiles of a collisional laser plasma. An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where the electron densities approach n[sub c]/10. Laser plasmas of this type are important because they model some of the aspects of the plasmas found in high-gain laser-fusion pellets irradiated by long pulse widths where the laser light is absorbed mostly in the corona. The experimental results and LASNEX simulations agree within a percent standard deviation of 40% for the electron density and 50% for the sound speed and radial drift velocity. Thus it is shown that the hydrodynamics equations with classical coefficients and the numerical approximations in LASNEX are valid models of laser-heated, highly collisional plasmas. The versatility of Thomson scattering is expanded upon by extending existing theory with a Fokker-Planck based model to include plasmas that are characterized by (0 [le] k[sub ia][lambda][sub ii] [le] [infinity]) and ZT[sub e]/T[sub i], where k[sub ia] is the ion- acoustic wave number, [lambda][sub ii] is the ion-ion mean free path, Z is the ionization state of the plasma, and T[sub e], T[sub i] are the electron and ion temperatures in electron volts respectively. The model is valid for plasmas in which the electrons are approximately collisionless, (k[sub ia][lambda][sub ei], k[sub ia][lambda][sub ee] [ge] 1), and quasineutrality holds, ([alpha] [much-gt]1), where [alpha] = 1/k[lambda][sub DE] and [lambda][sub DE] is the electron Debye length. This newly developed model predicts the lineshape of the ion-acoustic Thomson spectra and when fit to experimental data provides a direct measurement of the relative thermal flow velocity between the electrons and ions.
Download or read book New Regime of Thomson Scattering Probing Dense Plasmas with X Ray Lasers written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors demonstrate through calculations and theoretical analysis the first application of a x-ray laser for probing hot, high-density plasmas (n[sub e][ge] 10[sup 23] cm[sup -3]) using a Ni-like transient collisional excitation x-ray laser as a probe. Theoretical predictions are used to diagnose the electron temperature in short pulse (500 fs) laser produced plasmas. The threshold power of the x-ray probe is estimated by comparing theoretical scattering levels with plasma thermal emission. The necessary spectral resolution of the instrument sufficient for resolving electron temperature is given.
Download or read book Thomson Scattering from Near solid Density Plasmas Using Soft X ray Free Electron Lasers written by and published by . This book was released on 2006 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.
Download or read book Modeling of Thomson Scattering Spectra in High z Laser Produced Plasmas written by and published by . This book was released on 1998 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical calculations of a Thomson scattering cross section and dynamical form factors are presented for high-Z laser produced inhomogeneous plasmas. Relevance of these results to astrophysical plasmas is pointed out. Comparisons with recent experimental observations are discussed with emphasis on the effects of plasma inhomogeneity, ion-ion collisions and non-Maxwellian distribution functions.
Download or read book Plasmas and Laser Light written by Thomas Peter Hughes and published by John Wiley & Sons. This book was released on 1975 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Use of Ultraviolet Thomson Scattering as a Versatile Diagnostic for Detailed Measurements of a Collisional Laser Produced Plasma written by Mark David Tracy and published by . This book was released on 1993 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
