scholarly journals Semi-classical calculation of atomic processes and numerical simulation of dense plasmas

1994 ◽  
Vol 12 (2) ◽  
pp. 245-255
Author(s):  
R.M. More
Keyword(s):  
Energy Exchange ◽  
Equations Of State ◽  
Dense Plasma ◽  
Atomic Data ◽  
Coupling Coefficients ◽  
Atomic Processes ◽  
Dense Plasmas ◽  
First Approximation ◽  
Quantum Statistical ◽  
Classical Calculation

Modern numerical simulations of hot dense plasma require atomic data including equations of state, opacities, and coupling coefficients for energy exchange between photons, electrons, and fast and thermal ions. While these coefficients may be calculated by complicated quantum-statistical theories, in many cases the simpler semi-classical theory gives a reasonably accurate first approximation.

Equations of State for Natural and Synthetic Rubber-Like Materials. I Unaccelerated Natural Soft Rubber

1943 ◽  
Vol 16 (2) ◽  
pp. 297-309 ◽  
Author(s):  
R. L. Anthony ◽  
R. H. Caston ◽  
Eugene Guth
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Equations Of State ◽  
Intermolecular Forces ◽  
Theoretical Expression ◽  
Total Force ◽  
Inversion Point ◽  
Synthetic Rubber ◽  
First Approximation ◽  
Direct Contrast

Abstract Summarizing, the following important conclusions may be drawn from these experiments on a typical unaccelerated soft gum compound. 1. The existence of the inversion point in the stress-temperature curves is shown to be due solely to ordinary volume thermal expansion, and may be eliminated by correcting for this thermal expansion. 2. The curves given in Figure 8a show that, for compounds of this type, the change of entropy with elongation accounts for more than 90 per cent of the total stress at room temperature, while the internal-energy contribution is less than 10 per cent and, to a first approximation, may be neglected. In other words, the retractive force is due almost entirely to the tendency of the extended rubber molecules to return to a less ordered curled-up state. This is in direct contrast to the elasticity exhibited by ordinary bodies, in which case elasticity is due to intermolecular forces. 3. The contribution of the entropy force to the total force is well represented by the theoretical expression of James and Guth. This agreement constitutes our main reason for interpreting the entropy force as being due to the kinetic motion of the rubber molecules.

The application of intense ion beams to the creation of hot dense plasmas

1981 ◽  
Vol 300 (1456) ◽  
pp. 613-621 ◽  
Keyword(s):  
Heavy Ions ◽  
Dense Plasma ◽  
Ion Beams ◽  
Current Understanding ◽  
Dense Plasmas ◽  
Current Thinking ◽  
Ion Energies ◽  
Light Ions ◽  
Small Targets ◽  
Thermonuclear Ignition

A broad review is presented of the physics central to the production of hot dense plasmas by intense ion beams. Particular attention is paid to the reasons for using ion beams rather than lasers. By using simple laws the required beam intensities and ion energies for light ions (protons, deuterons, etc.) and heavy ions ( A > 120) are compared. Current understanding of ion-dense plasma interactions is discussed together with current thinking on possible accelerator sources of intense beams and their final transport to small targets. Emphasis is placed throughout on the use of ion beams for heating targets of deuterium-tritium mixtures to thermonuclear ignition.

scholarly journals Excitation of ion wakefields by electromagnetic pulses in dense plasmas

2009 ◽  
Vol 75 (1) ◽  
pp. 15-18 ◽  
Author(s):  
P. K. SHUKLA
Keyword(s):  
Wave Equation ◽  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Pulse ◽  
Dense Plasma ◽  
Ponderomotive Force ◽  
Electromagnetic Pulses ◽  
Dense Plasmas ◽  
High Energies

AbstractThe excitation of electrostatic ion wakefields by electromagnetic pulses in a very dense plasma is considered. For this purpose, a wave equation for the ion wakefield in the presence of the ponderomotive force of the electromagnetic waves is obtained. Choosing a typical profile for the electromagnetic pulse, the form of the ion wakefields is deduced. The electromagnetic wave-generated ion wakefields can trap protons and accelerate them to high energies in dense plasmas.

scholarly journals Diagnostic potential of advanced X-ray spectroscopy for investigation of hot dense plasmas

2004 ◽  
Vol 22 (1) ◽  
pp. 25-28 ◽  
Author(s):  
O. RENNER ◽  
I. USCHMANN ◽  
E. FÖRSTER
Keyword(s):  
Dense Plasma ◽  
X Ray ◽  
Dense Plasmas ◽  
Plasma Diagnosis ◽  
Bent Crystal ◽  
Complex Information ◽  
Diagnostic Potential ◽  
Vertical Dispersion ◽  
Fundamental Research

Modern experimental methods and instruments for X-ray spectral investigation of hot dense plasma provide complex information on environmental conditions in extreme states of matter. The basic spectroscopic conceptions for K-shell plasma diagnosis are outlined, the main characteristics of toroidally bent crystal spectrometers and vertical-dispersion instruments are briefly reviewed. Selected applications (monitoring and optimization of the emission from the femtosecond-laser-produced plasmas, characterization of colliding laser-exploded foils, spectral line merging, and continuum lowering in constrained-flow plasmas) demonstrate the usefulness of advanced spectroscopic methods for plasma diagnostics and fundamental research.

scholarly journals Generation of hot and dense plasmas in laser accelerated colliding foil systems

1998 ◽  
Vol 16 (1) ◽  
pp. 21-30 ◽  
Author(s):  
P. Angelo ◽  
H. Derfoul ◽  
P. Gauthier ◽  
P. Sauvan ◽  
A. Poquerusse ◽  
...  
Keyword(s):  
Thermal Conduction ◽  
Focal Spot ◽  
Laser Intensity ◽  
Dense Plasma ◽  
Lateral Expansion ◽  
Dense Plasmas ◽  
Monochromatic Imaging ◽  
Thin Foils ◽  
Plasma Effects ◽  
Good Agreement

We create hot (Te > 200 eV) and dense (Ne > 1023 cm−3) plasmas in the colliding zone of two thin foils accelerated by two laser beams of the LULI facilities. Three spectroscopic diagnostics (two 1D space-resolved spectrographs and a 2D monochromatic imaging) are used to drive the efficiency of the compression. We show that 2D effects are important. Realistic simulations of these experiments must be done, taking into account the inhomogeneity of the laser intensity in the focal spot, the foil distorsion, the plasma lateral expansion, and the lateral thermal conduction. Two-dimensional LASNEX code results are in good agreement with our experimental results. The optimized compressed plasmas generated are favorable for the exhibition of dense plasma effects due to molecular formations, and they reproduce in laboratory some astrophysical situations.

Quantum-statistical T-matrix approach to line broadening of hydrogen in dense plasmas

2010 ◽  
Author(s):  
Sonja Lorenzen ◽  
August Wierling ◽  
Heidi Reinholz ◽  
Gerd Röpke ◽  
Mark C. Zammit ◽  
...  
Keyword(s):  
Matrix Approach ◽  
Line Broadening ◽  
Dense Plasmas ◽  
T Matrix ◽  
Quantum Statistical

scholarly journals Analysis of directly driven ICF targets

1986 ◽  
Vol 4 (3-4) ◽  
pp. 349-392 ◽  
Author(s):  
G. Velarde ◽  
J. M. Aragones ◽  
J. A. Gago ◽  
L. Gamez ◽  
M. C. Gonzalez ◽  
...  
Keyword(s):  
Equations Of State ◽  
Radiation Transport ◽  
Simulation Models ◽  
Computational Procedure ◽  
Particle Beam ◽  
Heavy Ion ◽  
Atomic Data ◽  
Discrete Ordinates ◽  
Particle In Cell ◽  
Charged Particle Transport

In this article the current capabilities at DENIM for the analysis of directly driven targets are presented. These include theoretical, computational and applied physical studies and developments of detailed simulation models for the most relevant processes in ICF. The simulation of directly driven ICF targets is carried out with the one-dimensional NORCLA code developed at DENIM. This code contains two main segments: NORMA and CLARA, able to work fully coupled and in an iterative manner. NORMA solves the hydrodynamic equations in a lagrangian mesh. It has modular programs coupled to it to treat the laser or particle beam interaction with matter. Equations of state, opacities and conductivities are taken from a DENIM atomic data library, generated externally with other codes that will also be explained in this work. CLARA solves the transport equation for neutrons, (Boltzmann), as well as for charged particles, and suprathermal electrons (Fokker-Planck), using discrete ordinates and finite element methods in the computational procedure. Parametric calculations of multilayered single-shell targets driven by heavy ion beams are also analyzed. Finally, conclusions are focused on the ongoing developments in the areas of interest such as: radiation transport, atomic physics, particle in cell method, charged particle transport, two-dimensional calculations and instabilities.

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