Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
Collective Thomson scattering is widely used to measure bulk plasma parameters in high density, laser-produced plasmas, and is used to detect plasma waves from instabilities. However, inhomogeneity in these small plasmas often leads to a spectrum with insufficient resolution to discern phenomena such as wave damping and nonlinear wave effects. Two techniques are discussed for laser-produced plasmas to overcome these limitations, and provide details of wave damping and nonlinear behavior. First, imaging Thomson scattering is used to obtain spatially-resolved plasma wave profiles in a 100-200 eV plasma, and allows us to infer ion-ion collisional damping rates. Second, a diffraction-limited laser beam is used to drive stimulated Raman scattering (SRS) in a hot plasma, generating large amplitude Langmuir waves. The comparatively small interaction volume permits sufficient spectral resolution to observe nonlinear wave behavior, previously unresolved in other experiments.
Detailed Characterization of Plasma Wave Behavior Using Collective Thomson Scattering
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
Collective Thomson scattering is widely used to measure bulk plasma parameters in high density, laser-produced plasmas, and is used to detect plasma waves from instabilities. However, inhomogeneity in these small plasmas often leads to a spectrum with insufficient resolution to discern phenomena such as wave damping and nonlinear wave effects. Two techniques are discussed for laser-produced plasmas to overcome these limitations, and provide details of wave damping and nonlinear behavior. First, imaging Thomson scattering is used to obtain spatially-resolved plasma wave profiles in a 100-200 eV plasma, and allows us to infer ion-ion collisional damping rates. Second, a diffraction-limited laser beam is used to drive stimulated Raman scattering (SRS) in a hot plasma, generating large amplitude Langmuir waves. The comparatively small interaction volume permits sufficient spectral resolution to observe nonlinear wave behavior, previously unresolved in other experiments.
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
Collective Thomson scattering is widely used to measure bulk plasma parameters in high density, laser-produced plasmas, and is used to detect plasma waves from instabilities. However, inhomogeneity in these small plasmas often leads to a spectrum with insufficient resolution to discern phenomena such as wave damping and nonlinear wave effects. Two techniques are discussed for laser-produced plasmas to overcome these limitations, and provide details of wave damping and nonlinear behavior. First, imaging Thomson scattering is used to obtain spatially-resolved plasma wave profiles in a 100-200 eV plasma, and allows us to infer ion-ion collisional damping rates. Second, a diffraction-limited laser beam is used to drive stimulated Raman scattering (SRS) in a hot plasma, generating large amplitude Langmuir waves. The comparatively small interaction volume permits sufficient spectral resolution to observe nonlinear wave behavior, previously unresolved in other experiments.
Plasma Scattering of Electromagnetic Radiation
Author: John Sheffield
Publisher: Academic Press
ISBN: 0080952038
Category : Science
Languages : en
Pages : 512
Book Description
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
Publisher: Academic Press
ISBN: 0080952038
Category : Science
Languages : en
Pages : 512
Book Description
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
Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures Less Than 1 KeV
Author: James Steven Ross
Publisher:
ISBN: 9781124339498
Category :
Languages : en
Pages : 88
Book Description
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
Publisher:
ISBN: 9781124339498
Category :
Languages : en
Pages : 88
Book Description
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
Plasma Waves, 2nd Edition
Author: Donald Gary Swanson
Publisher: CRC Press
ISBN: 9780750309271
Category : Science
Languages : en
Pages : 960
Book Description
Extended and revised, Plasma Waves, 2nd Edition provides essential information on basic formulas and categorizes the various possible types of waves and their interactions. The book includes modern and complete treatments of electron cyclotron emission, collisions, relativistic effects, Landau damping, quasilinear and nonlinear wave theory, and tunneling equations. The broad scope encompasses waves in cold, warm, and hot plasmas and relativistic plasma waves. Special chapters deal with the effects of boundaries, inhomogeneities, and nonlinear effects. The author derives all formulae and describes several fundamental wave experiments, allowing for a greater appreciation of the subject.
Publisher: CRC Press
ISBN: 9780750309271
Category : Science
Languages : en
Pages : 960
Book Description
Extended and revised, Plasma Waves, 2nd Edition provides essential information on basic formulas and categorizes the various possible types of waves and their interactions. The book includes modern and complete treatments of electron cyclotron emission, collisions, relativistic effects, Landau damping, quasilinear and nonlinear wave theory, and tunneling equations. The broad scope encompasses waves in cold, warm, and hot plasmas and relativistic plasma waves. Special chapters deal with the effects of boundaries, inhomogeneities, and nonlinear effects. The author derives all formulae and describes several fundamental wave experiments, allowing for a greater appreciation of the subject.
Electron Velocity Distribution Functions and Thomson Scattering
Author: Avram L. Milder
Publisher:
ISBN:
Category :
Languages : en
Pages : 145
Book Description
"Statistical mechanics governs the fundamental properties of many body systems and the corresponding velocity distributions dictates most material properties. In plasmas, a description through statistical mechanics is challenged by the fact that the movement of one electron effects many others through their Coulomb interactions, leading to collective motion. Although most of the research in plasma physics assumes equilibrium electron distribution functions, or small departures from a Maxwell-Boltzmann (Maxwellian) distribution, this is not a valid assumption in many situations. Deviations from a Maxwellian distribution can have significant ramifications on the interpretation of diagnostic signatures, and more importantly in our ability to understand the basic nature of plasmas. Optical collective Thomson scattering provides precise density and temperature measurements in numerous plasma-physics experiments. A statistically based, quantitative analysis of the errors in the measured electron density and temperature is presented when synthetic data calculated using a non-Maxwellian electron distribution function is fit assuming a Maxwellian electron distribution [A. L. Milder et al., Phys. Plasmas 26, 022711 (2019)]. In the specific case of super-Gaussian distributions, such analysis lead to errors of up to 50% in temperature and 30% in density. Including the proper family of non-Maxwellian electron distribution functions, as a fitting parameter, in Thomson-scattering analysis removes the model-dependent errors in the inferred parameters at minimal cost to the statistical uncertainty. This technique was used to determine the picosecond evolution of non-Maxwellian electron distribution functions in a laser-produced plasma using utrafast Thomson scattering [A. L. Milder et al., Phys. Rev. Lett. 124, 025001 (2020)]. During the laser heating, the distribution was measured to be approximately super-Gaussian due to inverse bremsstrahlung heating. After the heating laser turned off, collisional ionization caused further modification to the distribution function while increasing electron density and decreasing temperature. Electron distribution functions were determined using Vlasov-Fokker-Planck simulations including atomic kinetics. A novel technique that encodes the electron motion to the frequency of scattered light while using collective scattering to improve the scattering efficiency at velocities where the number of electrons are limited was invented to measure non-Maxwellian electron distributions [A. L. Milder et al., in review Phys. Rev. Lett. (2021)]. This angularly resolved Thomson-scattering technique is a novel extension of Thomson scattering, enabling the measurement of the electron velocity distribution function over many orders of magnitude. Electron velocity distribution functions driven by inverse bremsstrahlung heating were measured to be super-Gaussian in the bulk (v/vth 3) and Maxwellian in the tail (v/vth 3) when the laser heating rate dominated over the electron-electron thermalization rate. Simulations with the particle code Quartz showed the shape of the tail was dictated by the uniformity of the laser heating. The reduction of electrons at slow velocities resulted in a ? 40% measured reduction in inverse bremsstrahlung absorption. A reduced model describing the distribution function is given and used to perform a Monte Carlo analysis of the uncertainty in the measurements [A. L. Milder et al., in review Phys. Plasmas (2021)]. The electron density and temperature were determined to a precision of 12% and 21%, respectively, on average while all other parameters defining the distribution function were generally determined to better than 20%. It was found that these uncertainties were primarily due to limited signal to noise and instrumental effects. Distribution function measurements with this level of precision were sufficient to distinguish between Maxwellian and non-Maxwellian distribution functions"--Pages viii-x.
Publisher:
ISBN:
Category :
Languages : en
Pages : 145
Book Description
"Statistical mechanics governs the fundamental properties of many body systems and the corresponding velocity distributions dictates most material properties. In plasmas, a description through statistical mechanics is challenged by the fact that the movement of one electron effects many others through their Coulomb interactions, leading to collective motion. Although most of the research in plasma physics assumes equilibrium electron distribution functions, or small departures from a Maxwell-Boltzmann (Maxwellian) distribution, this is not a valid assumption in many situations. Deviations from a Maxwellian distribution can have significant ramifications on the interpretation of diagnostic signatures, and more importantly in our ability to understand the basic nature of plasmas. Optical collective Thomson scattering provides precise density and temperature measurements in numerous plasma-physics experiments. A statistically based, quantitative analysis of the errors in the measured electron density and temperature is presented when synthetic data calculated using a non-Maxwellian electron distribution function is fit assuming a Maxwellian electron distribution [A. L. Milder et al., Phys. Plasmas 26, 022711 (2019)]. In the specific case of super-Gaussian distributions, such analysis lead to errors of up to 50% in temperature and 30% in density. Including the proper family of non-Maxwellian electron distribution functions, as a fitting parameter, in Thomson-scattering analysis removes the model-dependent errors in the inferred parameters at minimal cost to the statistical uncertainty. This technique was used to determine the picosecond evolution of non-Maxwellian electron distribution functions in a laser-produced plasma using utrafast Thomson scattering [A. L. Milder et al., Phys. Rev. Lett. 124, 025001 (2020)]. During the laser heating, the distribution was measured to be approximately super-Gaussian due to inverse bremsstrahlung heating. After the heating laser turned off, collisional ionization caused further modification to the distribution function while increasing electron density and decreasing temperature. Electron distribution functions were determined using Vlasov-Fokker-Planck simulations including atomic kinetics. A novel technique that encodes the electron motion to the frequency of scattered light while using collective scattering to improve the scattering efficiency at velocities where the number of electrons are limited was invented to measure non-Maxwellian electron distributions [A. L. Milder et al., in review Phys. Rev. Lett. (2021)]. This angularly resolved Thomson-scattering technique is a novel extension of Thomson scattering, enabling the measurement of the electron velocity distribution function over many orders of magnitude. Electron velocity distribution functions driven by inverse bremsstrahlung heating were measured to be super-Gaussian in the bulk (v/vth 3) and Maxwellian in the tail (v/vth 3) when the laser heating rate dominated over the electron-electron thermalization rate. Simulations with the particle code Quartz showed the shape of the tail was dictated by the uniformity of the laser heating. The reduction of electrons at slow velocities resulted in a ? 40% measured reduction in inverse bremsstrahlung absorption. A reduced model describing the distribution function is given and used to perform a Monte Carlo analysis of the uncertainty in the measurements [A. L. Milder et al., in review Phys. Plasmas (2021)]. The electron density and temperature were determined to a precision of 12% and 21%, respectively, on average while all other parameters defining the distribution function were generally determined to better than 20%. It was found that these uncertainties were primarily due to limited signal to noise and instrumental effects. Distribution function measurements with this level of precision were sufficient to distinguish between Maxwellian and non-Maxwellian distribution functions"--Pages viii-x.
Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures Less Than 1 KeV.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 111
Book Description
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
Publisher:
ISBN:
Category :
Languages : en
Pages : 111
Book Description
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
The Theory of Plasma Waves
Scientific and Technical Aerospace Reports
ERDA Research Abstracts
Author: United States. Energy Research and Development Administration
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1040
Book Description
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1040
Book Description
Collective Thomson Scattering Measurements of Ion-acoustic Wave Broadening in Moderately Coupled, Moderately Collisional Plasmas
Author: Thomas Edward Tierney
Publisher:
ISBN:
Category : Collisions (Physics)
Languages : en
Pages : 402
Book Description
Publisher:
ISBN:
Category : Collisions (Physics)
Languages : en
Pages : 402
Book Description