Nonlinear radio-frequency response of a non-uniform plasma slab–condenser system with realistic density and velocity profiles

1972 ◽  
Vol 8 (2) ◽  
pp. 113-126 ◽  
Author(s):  
R. Ballieu ◽  
A. M. Messiaen ◽  
P. E. Vandenplas
Keyword(s):  
Plasma Sheath ◽  
Nonlinear Behaviour ◽  
Bounded Plasma ◽  
Plasma Slab ◽  
Order Of Magnitude ◽  
Classical Plasma ◽  
Sophisticated Model ◽  
Density Perturbations ◽  
Remarkable Agreement ◽  
Uniform Plasma

The nonlinear behaviour of a realistic one-dimensional bounded plasma (specifically, the classical plasma slab–condenser system) is computed by an iterative perturbation method. The results indicate, somewhat unexpectedly, that the influence of the r.f. field on the static density profile and on the resonance spectrum is much smaller than would have been inferred from a previous analysis of an unbounded plasma. However, this approach is inherently limited by the fact that, even for not too high r.f. fields, the electron density perturbations can become of the same order of magnitude as the static density in the tenuous plasma sheath near the wall. The resonance curves obtained with this sophisticated model show quite remarkable agreement with existing experimental data.

scholarly journals COMPARISON BETWEEN THE RESULTS OF LITTORAL-DRIFT COMPUTATIONS AND CUBATURE OF DEPOSITS IN A DREDGED CHANNEL

1974 ◽  
Vol 1 (14) ◽  
pp. 42
Author(s):  
V.F. Motta ◽  
J.V. Bandeira
Keyword(s):  
Time Interval ◽  
Littoral Drift ◽  
Monthly Basis ◽  
Wave Characteristics ◽  
Order Of Magnitude ◽  
Annual Volume ◽  
Offshore Oil ◽  
Remarkable Agreement

The total annual volume of littoral drift on either side of the mouth of Sergipe estuary, in the Northeast of Brazil, has been de_ termined by applying Caldwell's, Castanho's and Bijker's methods to the wave characteristics that had been recorded at a twenty-metre depth of water, over a whole year, for the design of an offshore oil terminal. The three computation methods yielded the same order of maj> nitude which was found to amount to about 80000Om^/year. The dominant drift is s outhwes tward, and its predicted amount is 660000m-*/year. It was also found that although the three methods lead to total re suits of the same order of magnitude, they do not agree as to the vari^ ation of littoral drift over the year for the s ame waves. An eight-metre deep shipping channe 1 has been dredgedaccross the bar. The channel was surveyed in December 1971, August and Decem ber 1972, and a cubature of the deposits was made after the littoraldrift computations had been carried out. As the latter had been per formed on a monthly basis, a comparison became possible between pre dieted and actual volumes of deposits for the same lengths of time. The predicted volumes for the whole year were found to be from 34 to 46% greater than the actual results. However, for the time interval August-December 1972 a remarkable agreement was found be^ tween predicted and actual results.

Ultra-Shallow Doping of GaAs with Mg, Cr, Mn and B Using Plasma Stimulated Room-Temperature Diffusion

2020 ◽  
Vol 20 (3) ◽  
pp. 1878-1883
Author(s):  
Lei Li ◽  
Ruixiang Hou ◽  
Lili Zhang ◽  
Yihang Chen ◽  
L. Yao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Physical Mechanism ◽  
Plasma Sheath ◽  
Main Role ◽  
External Bias ◽  
Temperature Diffusion ◽  
Plasma Doping ◽  
Order Of Magnitude ◽  
Impurity Ion ◽  
First Time

It is demonstrated that Mg, Cr, Mn and B can be doped close to GaAs surface by plasma doping without external bias at room temperature (RT). The process only takes a few minutes, and impurity densities in the range of 1018–1021/cm3 can be achieved with doping depths about twenty nanometers. The experiment results are analyzed and the physical mechanism is tentatively explained as follows: during the doping process, impurity ion implantation under plasma sheath voltage takes place, simultaneously, plasma stimulates RT diffusion of impurity atom, which plays the main role in the doping process. The enhanced RT diffusion coefficients of Mg, Cr, Mn and B in GaAs are all in the order of magnitude of 10-15 cm2sec-1. This is reported for the first time among all kinds of plasma assisted doping methods.

On the theory of plasma–sheath resonance in a non-uniform plasma

1999 ◽  
Vol 61 (3) ◽  
pp. 469-488 ◽  
Author(s):  
NOBORU TANIZUKA ◽  
JOHN E. ALLEN
Keyword(s):  
Resonant Frequency ◽  
Plasma Frequency ◽  
Inhomogeneous Plasma ◽  
Plasma Sheath ◽  
Entire System ◽  
Local Resonance ◽  
Uniform Plasma

Calculations are presented on the phenomenon of plasma–sheath resonance in an inhomogeneous plasma. In certain cases, this resonance coincides with a local resonance occurring in the plasma, the local plasma frequency being equal to the resonant frequency of the entire system. The theory does not describe the mechanism of absorption, but does predict the magnitude of the power involved. Some limitations of the theory are discussed.

Reflection Properties of Electromagnetic Wave in a Bounded Plasma Slab

2010 ◽  
Vol 38 (12) ◽  
pp. 3348-3355 ◽  
Author(s):  
C. X. Yuan ◽  
Z. X. Zhou ◽  
H. G. Sun
Keyword(s):  
Electromagnetic Wave ◽  
Bounded Plasma ◽  
Plasma Slab

The electrostatic eigenmodes of a cold plasma with a two-dimensional density non-uniformity

1985 ◽  
Vol 34 (2) ◽  
pp. 305-312
Author(s):  
E. Näslund ◽  
O. M. Gradov
Keyword(s):  
Surface Waves ◽  
Cold Plasma ◽  
Resonant Absorption ◽  
Two Dimensional ◽  
Surface Oscillation ◽  
Plasma Slab ◽  
Uniform Plasma ◽  
Eigenfrequency Spectrum

A new kind of surface oscillation, which can exist when the usual surface waves are absent because of resonant absorption, has been studied for a non-uniform plasma slab. Special attention is paid to the influence of the boundaries on the eigenfrequency spectrum.

scholarly journals The impact of progenitor asymmetries on the neutrino-driven convection in core-collapse supernovae

2020 ◽  
Vol 494 (4) ◽  
pp. 5360-5373 ◽  
Author(s):  
Rémi Kazeroni ◽  
Ernazar Abdikamalov
Keyword(s):  
Buoyant Density ◽  
Three Dimensional ◽  
Core Collapse ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Post Shock ◽  
Nuclear Burning ◽  
Density Perturbations ◽  
Perturbation Parameters ◽  
The Impact

ABSTRACT The explosion of massive stars in core-collapse supernovae may be aided by the convective instabilities that develop in their innermost nuclear burning shells. The resulting fluctuations support the explosion by generating additional turbulence behind the supernova shock. It was suggested that the buoyant density perturbations arising from the interaction of the pre-collapse asymmetries with the shock may be the primary contributor to the enhancement of the neutrino-driven turbulent convection in the post-shock region. Employing three-dimensional numerical simulations of a toy model, we investigate the impact of such density perturbations on the post-shock turbulence. We consider a wide range of perturbation parameters. The spatial scale and the amplitude of the perturbations are found to be of comparable importance. The turbulence is particularly enhanced when the perturbation frequency is close to that of the convective turnovers in the gain region. Our analysis confirms that the buoyant density perturbations is indeed the main source of the additional turbulence in the gain region, validating the previous order-of-magnitude estimates.

scholarly journals Ultra-intense attosecond pulses emitted from laser wakefields in non-uniform plasmas

2013 ◽  
Vol 31 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Y. Liu ◽  
F.Y. Li ◽  
M. Zeng ◽  
M. Chen ◽  
Z.M. Sheng
Keyword(s):  
Current Sheet ◽  
Attosecond Pulse ◽  
Pulse Emission ◽  
Dense Plasmas ◽  
Left Behind ◽  
Transverse Current ◽  
Uniform Region ◽  
Attosecond Pulses ◽  
Plasma Slab ◽  
Uniform Plasma

AbstractA scheme of generating ultra-intense attosecond pulses in ultra-relativistic laser interaction with under-dense plasmas is proposed. The attosecond pulse emission is caused by an oscillating transverse current sheet formed by an electron density spike composed of trapped electrons in the laser wakefield and the residual transverse momentum of electrons left behind the laser pulse when its front is strongly modulated. As soon as the attosecond pulse emerges, it tends to feed back to further enhance the transverse electron momentum and the transverse current. Consequently, the attosecond pulse is enhanced and developed into a few cycles later until the density spike is depleted out due to the pump laser depletion. To control the formation of the transverse current sheet, a non-uniform plasma slab with an up-ramp density profile in front of a uniform region is adopted, which enables one to obtain attosecond pulses with higher amplitudes than that in a uniform plasma slab.

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