摘要:

A criterion for predicting the transverse spacing dimensions in gas phase detonations is developed. The criterion depends upon the collision of wave fronts to form new reaction centers which eventually lead to the formation of new cells. Calculated values of transverse spacing over a wide range of pressure, dilution and degree of overdrive in the hydrogen‐oxygen‐argon system are compared to experimental data for stoichiometric mixtures. The predicted values of spacing with no overdrive are about twice the experimental values. A minimum in the predicted spacing is found with overdrive as well as a cutoff value of overdrive for which the predicted spacing becomes infinite.

ISSN:0031-9171    

DOI:10.1063/1.1694932

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The hydrodynamical stability of a laser‐driven plasma is investigated by analytically and numerically solving the set of coupled conservation equations of hydrodynamics to first order. The calculations are illustrated by a series of graphs showing the time evolution of the state variables of a laser‐driven deuterium‐tritium fusion plasma.

ISSN:0031-9171    

DOI:10.1063/1.1694933

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The collisional processes which transfer momentum between counterstreaming plasmas are reviewed and applied to the example of a laser‐produced plasma expanding into a partially ionized background. Experimental measurements of the dependence of the ion flow field on collisional momentum transfer demonstrate the validity of the simplified treatment of collision processes which have been adopted. A numerical model which simulates the laser‐plasma interaction with the background confirms the importance of collisions in previous experimental studies of momentum coupling, and provides some insight into the distinction between collisional and collisionless flow regimes.

ISSN:0031-9171    

DOI:10.1063/1.1694934

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

When a transverse electric wave is incident on a plasma column with an axial density gradient, the resultant scattered field is not purely transverse electric, but also has a transverse magnetic component. The relative importance of the latter is strongly enhanced at the main resonance of the plasma cylinder, its absolute magnitude becoming great even for moderate values of the axial density gradient. The present study is limited to a perturbation analysis of the effect. The inclusion of this effect leads to a much closer agreement between theory and experiment in the positive column of a discharge than was the case for a previous theory which only accounted for transverse electric to transverse magnetic transformation due to plasma axial drift along the column.

ISSN:0031-9171    

DOI:10.1063/1.1694935

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Single‐particle motion of relativistic electrons in a cusped magnetic field has been studied both analytically and experimentally. The Lagrangian formulation is used to solve for the electron trajectories in some simple magnetic cusp configurations. A threshold energy for transmission through the cusp is found, and confirmed experimentally. Two different electron orbit off‐centering mechanisms are discussed; one arising from a nonzero radial component of particle velocity on the upstream side of the cusp transition, and another arising from the finite width of the cusp transition. Experiments are reported confirming the existence of these off‐centering mechanisms, and the results are compared with theoretical expectations.

ISSN:0031-9171    

DOI:10.1063/1.1694936

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Numerical simulation and analytic theory are used to study thez‐dependent equilibria of a charge neutralized, relativistic electron beam, subject to an applied axial electric field. The analytic theory consists of nonparaxial envelope equations derived from a finite temperature fluid model for relativistic beams. The application of the theory to the calculation of beam pinching in high‐current relativistic electron beam accelerator diodes is discussed. An effect of the applied electric field in the diode is to enhance beam pinching, for configurations relevant to both low‐ and high‐impedance diodes. In certain cases, the highly‐pinched beams have more energy in the random motion of the beam particles than in the longitudinal flow.

ISSN:0031-9171    

DOI:10.1063/1.1694937

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The propagation of electrostatic plasma waves, and their subsequent conversion into hot plasma waves at the lower hybrid frequency is calculated for realistic density profiles and finite rf sources in a slab geometry. A finite length slow wave source having a potential distribution &phgr; ∼ cosk0zis found to generate spatial oscillations having a well‐defined wavelength. These oscillations are confined to regions bounded by conical curves originating at the ends of the source. The axial distance of rf energy propagation to the lower hybrid layer is found to be greater than the radial distance of propagation by a factor of the order (mi/me)1/2. The conversion at the lower hybrid layer of the electrostatic cold plasma waves excited by a finite source into propagating hot plasma waves is calculated. It is shown that collisional damping at the lower hybrid layer may predominate over mode conversion even for relatively low collision frequencies.

ISSN:0031-9171    

DOI:10.1063/1.1694938

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The problem of a strongly driven one‐dimensional electrostatic plasma is treated by the method of expansion of the distribution function in terms of Hermite polynomials in velocity space. Numerical results for hydrodynamic variables are similar to those found in simulation calculations. The shapes of the ion and electron distribution functions are significantly altered from Maxwellian form during heating.

ISSN:0031-9171    

DOI:10.1063/1.1694939

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A set of model equations for the parametric instability that consist of damped harmonic oscillators coupled with a stochastic oscillatory driver is considered. With the assumption that the autocorrelation time of the stochastic part of the driver is very short, a solution for the average response of the oscillators is derived. This solution holds for arbitrary damping rates, unlike the results of previous authors. Threshold levels and growth rates for the parametric decay and oscillating two‐stream instabilities are found as a function of driver bandwidth.

ISSN:0031-9171    

DOI:10.1063/1.1694940

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The modified Korteweg‐de Vries equation appropriate to small amplitude, cylindrically symmetric ion acoustic waves is given. The numerical solution is obtained and compared with recent work on spherical solitons.

ISSN:0031-9171    

DOI:10.1063/1.1694941

出版商:AIP    

年代:1974

数据来源: AIP