Download or read book Thomson Scattering Measurements of Plasma Dynamics written by S. H. Glenzer and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors propose to investigate the dynamics of plasmas in the warm dense matter (WDM) regime on ultra-short time scales. Accessible plasma conditions are in the density range of n = 10{sup 20} - 10{sup 23} cm{sup -3} and at moderate temperatures of T = 1 - 20 eV. These plasmas are of importance for laboratory astrophysics, high energy density science and inertial confinement fusion. They are characterized by a coupling parameter of {Lambda} {approx}> 1, where electromagnetic interactions are of the same order as the kinetic energy. The high density of the plasma makes it opaque to radiation in the visible range and, as a consequence, UV up to x-ray radiation can be used to probe such systems. Therefore a wide range in the temperature-density plane of WDM is presently unexplored and only the VUV-FEL opens for the first time the opportunity for its detailed investigation. In equilibrium, the macroscopic state of the plasma is completely characterized by its density and temperature. In pump-probe experiments however, the plasma is initially in a nonequilibrium state and relaxes towards equilibrium within the relaxation time {tau}{sub R}. For t> {tau}{sub R}, the plasma is in an equilibrium state and expands hydrodynamically on a time scale {tau}{sub H}. The proposed experiment measures the time-resolved Thomson scattering signal with the VUV-FEL radiation characterizing the plasma in equilibrium and nonequilibrium states. Both regimes are extremely interesting and will provide new insight into the following phenomena: (1) details of nonequilibrium correlations, (2) relaxation phenomena, (3) hydrodynamic expansion, (4) recombination kinetics. The time-resolved Thomson scattering signal is obtained in a pump-probe experiment by varying the delay between pump and probe. The final stage of the relaxation process (t {approx} {tau}{sub R}) is of special interest since the plasma components (electrons and ion species) can be assumed to be in quasi-equilibrium. This allows for accurate measurements of the electron temperature using the detailed balance relation. For times t {approx}{tau}{sub R} the scattering spectrum provides also the plasmon damping in nonequilibrium from which information on the formation and decay of collective excitations at short time scales can be obtained. At large time scales (t {approx} {tau}{sub H}) the hydrodynamic expansion of the plasma sets in. Detailed information on the evolution of the plasma in this regime is available from sophisticated hydrodynamic computer simulations which can be tested with the proposed measurements. With the decreasing plasma density due to the expansion, recombination processes become important and need to be considered as well.
Download or read book The Dynamics of Electrons in Linear Plasma Devices and Its Impact on Plasma Surface Interaction written by Michael Hubeny and published by Springer. This book was released on 2019-02-15 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence in plasma surface interaction holds crucial uncertainties for its impact on material erosion in the operation of fusion reactors. In this thesis, the design, development and operation of a Thomson scattering diagnostic and its novel implementation with fast visual imaging created a versatile tool to investigate intermittently occuring plasma oscillations. Specifically, ballistic transport events in the plasma edge, constituting turbulent transport, have been targeted in this thesis. With the help of a custom photon counting algorithm, the conditional averaging technique was applied on Thomson scattering for the first time to allow spatial and pseudo-time-resolved measurements. Since plasma turbulence and the emerging transport phenomena are comparable in most magnetized devices, the diagnostic development and the results from the linear plasma device PSI-2 are useful for an implementation of similar techniques in larger fusion experiments. Furthermore, the obtained results indicate a strong enhancement of erosion with turbulent transport and thus underline the importance of dedicated experiments investigating plasma turbulence in the framework of erosion in future fusion reactors.
Download or read book Thomson Scattering Measurements on the High Beta Pinch Extrap T1 written by P. Karlsson and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thomson Scattering Measurements of Mast Plasmas written by R. M. Patrick and published by . This book was released on 1965 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of Thomson scattering from the plasma electrons were created by high speed shock waves in a magnetic annular shock tube (MAST) used to determine the electron density behind the shock waves, and some preliminary measurements of the electron velocity distribution. A Q-switch ruby laser furnished the light beam which was scattered by the plasma electrons. A rotating quartz prism furnished the Q-switching of the optical cavity for the ruby laser, and rather long Q-switched pulses were obtained (between 10 to the -7th power and 10 to the -6th power sec duration). The power level during the Q-switched pulse was between 30 and 100 megawatts. Rayleigh scattering from an air sample at various pressures was used to calibrate the power output of the laser and gave a simultaneous measure of the laser output power for all of the tests, while the Thomson scattering was being measured. The measurements of the electron density using the Thomson scattering and the plasma continuum intensities agreed within the scatter of the data. The electron temperature measurements obtained with the Thomson scattering showed that the electron temperature increased with increasing shock speed for a given initial condition. (Author).
Download or read book Molecular Origin of Background Light in Thomson Scattering Measurements written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The plasma background light in Thomson scattering measurements is often far higher than expected for a pure hydrogen plasma. The spectral distribution of light from three plasmas (duration: 1 ms to steady state; electron density: below 1012 to over 1014 cm−3; temperature: below 20 to over 1000 eV) and signal-to-noise and intensity data from the Thomson scattering systems used on them are compared with analytic estimates to show that in two of these plasmas molecular light dominates the spectrum, while in the other, molecular light is present, but bremsstrahlung is usually more intense. Knowledge of the mechanism for background light can aid in designing detection systems for Thomson scattering and provide information on the neutral species composition and effective charge of the plasma.
Download or read book Thomson Scattering Measurements of the Plasma Parameters in a Hollow anode with Ferroelectric Plasma Source written by Vladislav Vekselman and published by . This book was released on 2008 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Probes for Plasma Diagnostics written by John Douglas Swift and published by Iliffe. This book was released on 1969 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thomson Scattering Measurements on the High Beam Pinch Extrap T1 written by P. Karlsson and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Origin of Background Light in Thomson Scattering Measurements written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The plasma background light in Thomson scattering measurements is often far higher than expected for a pure hydrogen plasma. The spectral distribution of light from three plasmas (duration: 1 ms to steady state; electron density: below 1012 to over 1014 cm−3; temperature: below 20 to over 1000 eV) and signal-to-noise and intensity data from the Thomson scattering systems used on them are compared with analytic estimates to show that in two of these plasmas molecular light dominates the spectrum, while in the other, molecular light is present, but bremsstrahlung is usually more intense. Knowledge of the mechanism for background light can aid in designing detection systems for Thomson scattering and provide information on the neutral species composition and effective charge of the plasma.
Download or read book Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures Less Than 1 KeV written by James Steven Ross and published by . This book was released on 2010 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (T/e
Download or read book Thomson Scattering Measurement of a Collimated Plasma Jet Generated by a High power Laser System written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures Less Than 1 KeV written by and published by . This book was released on 2010 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (Te
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 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 Novel Theoretical Approaches in Thomas Laser Scattering Measurements in Weakly Nonideal Collisional and Inhomogenous Arc Plasma Jets written by Gianluca Gregori and published by . This book was released on 2001 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thomson Scattering Measurements of Plasma Turbulence Near Quarter critical Density in a CO2 Laser heated Gas Target Plasma written by Jack Jerome Schuss and published by . This book was released on 1978 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
