scholarly journals Direct- and indirect-driven reactor targets

1993 ◽  
Vol 11 (1) ◽  
pp. 97-107 ◽  
Author(s):  
K. Kiu
Keyword(s):  
Electromagnetic Waves ◽  
Laser Light ◽  
Target Surface ◽  
Small Region ◽  
Large Radius ◽  
Electron Motion ◽  
Target Structure ◽  
Beam Irradiation ◽  
Strong Light ◽  
Phase Mixing

Theoretical and numerical analyses are given for direct- and indirect-driven reactor targets, from which 3-GJ fusion output energy is released. For a reactor target, which has a large radius and long implosion time, supersonic flow of imploding D–T fuel in the converging nozzle (in sphere) is important for adiabatic compression of fuel. For a direct-driven target, pellet gain depends much upon the region where the beam deposits its energy. Phase mixing is also important to increase the absorption rate of irradiating laser light. When a strong light with a phase is concentrated on a small region of target surface, collective electron motion on the target surface radiates electromagnetic waves, which reduce the electron motion. When beam irradiation on the target is not uniform, an indirect-driven target must be used because a direct-driven target is weak for nonuniform irradiation. For an indirect-driven reactor target, which requires a long implosion time, expansion of radiator and absorber layers causes the decrease in radiation temperature. There is the optimum target structure with respect to the aspect ratio (radiation gap distance).

scholarly journals Beam generations of three kinds of charged particles

1991 ◽  
Vol 9 (1) ◽  
pp. 149-165 ◽  
Author(s):  
K. Niu ◽  
P. Mulser ◽  
L. Drska
Keyword(s):  
Electromagnetic Field ◽  
Electron Beam ◽  
Electromagnetic Waves ◽  
Laser Light ◽  
Ion Beam ◽  
Charged Particles ◽  
Leading Edge ◽  
Heavy Ion ◽  
Ion Beams ◽  
Damping Force

Analyses are given for beam generations of three kinds of charged particles: electrons, light ions, and heavy ions. The electron beam oscillates in a dense plasma irradiated by a strong laser light. When the frequency of laser light is high and its intensity is large, the acceleration of oscillating electrons becomes large and the electrons radiate electromagnetic waves. As the reaction, the electrons feel a damping force, whose effect on oscillating electron motion is investigated first. Second, the electron beam induces the strong electromagnetic field by its self-induced electric current density when the electron number density is high. The induced electric field reduces the oscillation motion and deforms the beam.In the case of a light ion beam, the electrostatic field, induced by the beam charge, as well as the electromagnetic field, induced by the beam current, affects the beam motion. The total energy of the magnetic field surrounding the beam is rather small in comparison with its kinetic energy.In the case of heavy ion beams the beam charge at the leading edge is much smaller in comparison with the case of light ion beams when the heavy ion beam propagates in the background plasma. Thus, the induced electrostatic and electromagnetic fields do not much affect the beam propagation.

scholarly journals The ferroelectric photo ground state of SrTiO3: Cavity materials engineering

2021 ◽  
Vol 118 (31) ◽  
pp. e2105618118
Author(s):  
Simone Latini ◽  
Dongbin Shin ◽  
Shunsuke A. Sato ◽  
Christian Schäfer ◽  
Umberto De Giovannini ◽  
...  
Keyword(s):  
Ground State ◽  
Small Region ◽  
First Principles Calculations ◽  
Strong Light ◽  
Optical Cavities ◽  
Materials Engineering ◽  
Matter Coupling ◽  
Quantum Paraelectric ◽  
New States ◽  
Properties Of Materials

Optical cavities confine light on a small region in space, which can result in a strong coupling of light with materials inside the cavity. This gives rise to new states where quantum fluctuations of light and matter can alter the properties of the material altogether. Here we demonstrate, based on first-principles calculations, that such light–matter coupling induces a change of the collective phase from quantum paraelectric to ferroelectric in the SrTiO3 ground state, which has thus far only been achieved in out-of-equilibrium strongly excited conditions [X. Li et al., Science 364, 1079–1082 (2019) and T. F. Nova, A. S. Disa, M. Fechner, A. Cavalleri, Science 364, 1075–1079 (2019)]. This is a light–matter hybrid ground state which can only exist because of the coupling to the vacuum fluctuations of light, a photo ground state. The phase transition is accompanied by changes in the crystal structure, showing that fundamental ground state properties of materials can be controlled via strong light–matter coupling. Such a control of quantum states enables the tailoring of materials properties or even the design of novel materials purely by exposing them to confined light.

scholarly journals Bio-capacitor consist of insulated myelin-sheath and uninsulated node of Ranvier: a bio-nano-antenna

2020 ◽  
Vol 10 (1) ◽  
pp. 4956-4965
Keyword(s):  
Nerve Cell ◽  
Myelin Sheath ◽  
Electromagnetic Waves ◽  
Node Of Ranvier ◽  
Quantum Effects ◽  
Small Region ◽  
Physiological Data ◽  
Membrane Thickness ◽  
Electrical Wire ◽  
Membrane Bound

Myelin consists of fatty molecules (lipids) which are located in the CNC (central nervous system) and as an insulator around nerve cell axons increases the velocities information to transit from one nerve cell to another tissue like an electrical wire (the axon) with insulating material (myelin) around it. Each axon contains multiple long myelinated parts separated from each other through short gaps called “Nodes of Ranvier” or myelin-sheath gaps. A computational model is presented for the simulation of propagated electromagnetic waves in a critical point between insulated myelin-sheath towards uninsulated node of Ranvier. The QM/MM calculation has been applied for generalizing the node of Ranvier results for computing action potentials and electro chemical behavior of membranes which agree with clusters of voltage-gated ion sodium and potassium channels. The node of Ranvier complexes is an accurate organization of membrane-bound aqueous compartments, and the model presented here represents electrophysiological events with combined realistic structural and physiological data. The quantum effects of different thicknesses in the mixed membranes of GalC/DPPC, have also been specifically investigated. It is shown that quantum effects can appear in a small region of free spaces within the membrane thickness due to the number and type of lipid’s layers. In addition, from the view point of quantum effects by Heisenberg rule, it is shown that quantum tunneling is allowed in some micro positions of membrane capacitor systems, while it is forbidden in other forms.

Solution of the Helmholtz equation for electromagnetic waves in an annular (segmented-annular) rectangular waveguide

2021 ◽  
Author(s):  
D.V. Semenov ◽  
D.S. Gudilin
Keyword(s):  
Electromagnetic Field ◽  
Helmholtz Equation ◽  
Rectangular Waveguide ◽  
Electromagnetic Waves ◽  
Point Of View ◽  
Practical Significance ◽  
Large Radius ◽  
Computing Systems ◽  
Bending Radius ◽  
Analytical Expressions

Formulation of the problem. When designing waveguides, spatial solutions are often in demand. However, from a methodological (including educational) point of view, mostly linear-extended structures with various sectional shapes are considered. The aim of this work is to consider a waveguide as a structure composed of segments bent in a plane with a certain radius. On the other hand, this solution is common for a plane-oriented waveguide path and, in the case of an infinitely large radius, converges to a solution for a straight waveguide. Practical significance. The presented solution of the Helmholtz equation for electromagnetic waves in an annular (segmentedannular) waveguide can be considered as a methodological basis for calculating a spatially oriented rectangular waveguide path. A step-by-step solution of the Helmholtz equation for a bent rectangular waveguide is presented; a methodology for determining the parameters of the electromagnetic field in a bent homogeneous waveguide is given. Expressions are derived for determining the parameters of the electromagnetic field components for waves of type E and H. General solutions are obtained that converge at an infinitely large bending radius to harmonic functions characteristic of solutions as applied to rectilinear waveguides. This technique can be applied both for analytical evaluation or numerical calculation and spatial modeling of waveguide parameters, and for designing the waveguide path as a whole. The presence of relatively simple analytical expressions greatly facilitates the task of analyzing and optimizing the waveguide path and building software and computing systems for their assessment, modeling and development.

Magnetron Sputtering Target Structure Optimization Research Status

2013 ◽  
Vol 318 ◽  
pp. 356-359
Author(s):  
Jing Lin ◽  
Jin Long Zhang ◽  
Gui Wen Yu
Keyword(s):  
Magnetic Field ◽  
Magnetron Sputtering ◽  
Magnetic Field Intensity ◽  
Structure Optimization ◽  
Target Surface ◽  
Simulation Method ◽  
Target Structure ◽  
Surface Magnetic Field ◽  
Target Field ◽  
Magnetic Field Simulation

In order to optimize the target surface magnetic field intensity and uniformity for the purpose, this paper introduces the traditional magnetron sputtering target problems, the author summarizes the other researchers on magnetron sputtering target field overall optimization ideas, magnetic field simulation method and different target under the condition of the magnet structure optimization, especially in rectangular target end area optimization are summarized, and the magnetron sputtering target magnetic field pole shoe and permeability piece optimization also made a description.

scholarly journals Interaction experiments of laser light with low density supercritical foams at the AEEF ABC facility

2000 ◽  
Vol 18 (1) ◽  
pp. 25-34 ◽  
Author(s):  
A. CARUSO ◽  
C. STRANGIO ◽  
S.Yu. GUS'KOV ◽  
V.B. ROZANOV
Keyword(s):  
Laser Light ◽  
Target Surface ◽  
Energy Coupling ◽  
Heat Diffusion ◽  
Low Density ◽  
Dense Phase ◽  
Pressure Work ◽  
Mechanical Coupling ◽  
Phase Dynamics ◽  
Target Plasma

Experiments have been performed on the interaction physics of laser light with polystyrene and agar–agar foams having average densities higher than critical. The experiments have been performed at the ABC facility of the Associazione EURATOM-ENEA sulla Fusione, in Frascati. The main addressed topics have been energy coupling (balance), diffusion of energy into the target, plasma and dense phase dynamics, and harmonics generation. The laser light (λ = 1.054 μm) was focused by a F/1 lens to produce on the target surface about 1.6 × 1014 W/cm2 (≈1015 W/cm2 in the waist, set about 100 μm inside the target). Experiments have shown efficient energy coupling (>80%) to be attributed to cavity formation in the low density foam (efficient light absorption) and good mechanical coupling of the plasma trapped in the cavity to the dense phase (ablation pressure work). Heat diffusion possibly plays a transitory role in the initial stages of the interaction (300–500 ps). Time integrated harmonics measurements revealed a blue-shifted 2ω and a red-shifted 5/2ω.

Characterization of a Commercial Gated Silicon Intensified Target Vidicon for Transient, Nonrepetitive Radiation Sources

1983 ◽  
Vol 37 (6) ◽  
pp. 531-537 ◽  
Author(s):  
J. Goldberg ◽  
R. Sacks
Keyword(s):  
Dynamic Range ◽  
Short Pulse ◽  
Target Surface ◽  
Plasma Generator ◽  
Small Region ◽  
Quantitative Information ◽  
Radiation Sources ◽  
Surface Saturation ◽  
Saturation Effects ◽  
Photographic Emulsions

Response linearity and dynamic range of a gated silicon intensified target vidicon multichannel detector are evaluated for applications involving short pulse, nonrepetitive exposure. A high intensity pulsed hollow cathode lamp and an electrically vaporized thin film plasma generator were used as radiation sources. Qualitative aspects of the vidicon are discussed by analogy with photographic emulsions. The effects of intensifier stage voltage on image intensity and focus are considered. Charging curves are presented for various electron beam scan times and for multiple as well as single interrogation scans. The effect of erase scans prior to the exposure on the shape of the charging curves also is considered. These charging curves suggest that target surface saturation effects result in very inefficient target charging, and multiple interrogation scans are required for quantitative information retrieval. The use of target preparation scans reduces charging efficiency. Using the intensifer gate pulse width for exposure control, plots of target response vs exposure are shown to be linear over at least two decades of exposure but only with multiple interrogation scans using long scan times on a small region of the target surface.

Sign in / Sign up

Export Citation Format

Share Document