scholarly journals Optical Transitions and Charge-Exchange in Highly Charged Quasi-Molecules

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
A. Devdariani ◽  
E. Dalimier ◽  
P. Sauvan
Keyword(s):  
Dense Plasma ◽  
Dipole Moments ◽  
Initial Approximation ◽  
Optical Transitions ◽  
Neutral Species ◽  
Nonrelativistic Case ◽  
Dense Plasmas ◽  
Nonadiabatic Transitions ◽  
Spectral Profiles ◽  
Bound Electron

The interaction between quasimolecular states produces not only nonadiabatic transitions but also some exotic features in the wings of the spectral profiles emitted by the ions in collision. Although this concept has been fruitfully used for neutral species, some new highlighted experimental data on quasimolecular optical transitions in hot dense plasma have renewed the interest to the concept in the recent years. The present review deals with highly charged quasimolecules and it is dedicated specifically to quasimolecules formed by two bare nuclei and one bound electron. The reason for this choice is that, for such quasimolecules, the energy terms and the dipole moments of the optical transitions can be obtained straightforwardly in nonrelativistic case without any approximation that are typical for neutrals. Although the results obtained in the frame of the approach developed here are directly applicable to the case of single collisions or to low-density plasmas, they form a reasonable initial approximation for the problem of optical profiles in hot dense plasmas and can be regarded as a safe framework for qualitative discussions of profiles in those environments.

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.

Widths of excited impurity levels in phosphorus-doped silicon

1983 ◽  
Vol 61 (1) ◽  
pp. 67-70 ◽  
Author(s):  
Robert Barrie ◽  
L. G. Parent ◽  
R. R. Parsons
Keyword(s):  
Ground State ◽  
Final States ◽  
Optical Transitions ◽  
Zero Temperature ◽  
Neutral Donor ◽  
Doped Silicon ◽  
Phosphorus Doped ◽  
Bound Electron ◽  
S States

A model is presented to explain the breadths of the excited impurity levels of phosphorus-doped silicon at zero temperature. The model assumes that the widths of optical transitions involving absorption by the neutral donor and so-called two-electron luminescence from an exciton bound to the neutral donor are the sums of level widths of the initial and final states. The excited s states' level widths are accounted for by assuming that they are governed by the lifetime of the levels for two-phonon decay to the ground state. This decay is brought about by the interaction of the bound electron with the phosphorus ion.

scholarly journals Improvements to ion-correlation experiments in dense plasmas

1992 ◽  
Vol 10 (1) ◽  
pp. 41-51 ◽  
Author(s):  
B. A. Shiwai ◽  
A. Djaoui ◽  
T. A. Hall ◽  
G. J. Tallents ◽  
S. J. Rose
Keyword(s):  
Good Accuracy ◽  
Dense Plasma ◽  
Coupling Parameter ◽  
Correlation Effects ◽  
X Ray ◽  
Dense Plasmas ◽  
Solid Density ◽  
X Ray Absorption ◽  
Good Agreement

Improved measurements of ion-correlation effects in a dense shock-compressed plasma are presented. The extended X-ray-absorption fine-structure (EXAFS) technique on the aluminum K edge is used to observe the short-range order within a dense plasma. Densities of about three times solid density were measured with good accuracy. The experimental measurements of density give results that are in good agreement with the MEDUSA onedimensional fluid code predictions. The improved quality of the data enabled us to calculate the ion coupling parameter during the compression and the subsequent heating of the plasma. An estimation of the temperature is given on the basis of published models, and an approximate agreement is obtained with the MEDUSA code predictions.

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.

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