摘要:

The ablative, quasi‐steady expansion of the spherical coronal plasma produced by irradiating an overdense pellet by a high‐intensity laser pulse, is studied for large ion charge numberZi. The entire structure of the flow and its changes as the laser power is increased, are determined. The instantaneous powerWrequired to generate a given ablation pressurePaand pellet radiusraat any time is determined in terms ofZi, ion massmi, and critical density; the mass ablation rate is also found. If the time lawPa(t) and (consequently)ra(t) for a desired optimal compression of the pellet are determined independently, the results allow one to obtain the laser power historyW(t) =W[Pa(t), ra(t), Zi, mi, @qLnc]. For a critical radius much larger thanra, most of the energy flows outward; this seems to invalidate known simple estimates of the relationW(Pa).

ISSN:0031-9171    

DOI:10.1063/1.863305

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

New time‐and‐space‐resolved measurements of the burn‐through of 0.05–0.34 &mgr;m thick plastic foils irradiated with 100 psec, 1.06 &mgr;m laser pulses at approximately 1016Wcm−1are presented. Comparison of the time history of the transparency of the foils with analytic and computational models suggests that the targets do not transmit until the density is well below the critical density. Comparison of the space‐resolved burn‐through measurements with an analytic model suggests that lateral thermal conduction is negligible. It is proposed that ion turbulence may be responsible for the high absorption and low thermal conductivity.

ISSN:0031-9171    

DOI:10.1063/1.863306

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A discussion is presented of the eigenvalues of the linear Be´nard–Marangoni stability problem. It is shown that the Marangoni number cannot be used as an eigenvalue parameter for the determination of an eigenvector set.

ISSN:0031-9171    

DOI:10.1063/1.863307

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The experimental analysis of a turbulent mixing layer shows, by means of a simple algorithm, that the vorticity is concentrated in individual cores of (a) half the strength corresponding to the initial instability and (b) dimensions appreciably smaller than the vorticity thickness of the mixing layer.

ISSN:0031-9171    

DOI:10.1063/1.863308

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The effect of collisions on ion gyroresonance in a magnetized plasma for frequencies &ohgr;≃n&OHgr;iis derived by solving the Fokker–Planck equation with a multiple‐time‐scale‐type perturbation method. An example is given forkai≫1 with a Landau collision operator.

ISSN:0031-9171    

DOI:10.1063/1.863309

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Numerical solutions of the electrostatic wave equations in a field‐angled, drifting Maxwellian magnetoplasma are fitted with measurements of lower oblique (Whistler) resonance‐cone angles. The drift velocities so deduced are consistent with the Child–Langmuir law.

ISSN:0031-9171    

DOI:10.1063/1.863310

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The expansion of an electron bunch is solved exactly in Lagrangian coordinates, and the result is compared to a self‐similar solution.

ISSN:0031-9171    

DOI:10.1063/1.863311

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Wave fronts and ray trajectories of electromagnetic modes radiated from a local source are obtained in an inhomogeneous magnetoplasma waveguide. They are investigated numerically using a kinetic theory at frequencies below the electron cyclotron frequency.

ISSN:0031-9171    

DOI:10.1063/1.863282

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The separatrix profile of a purely poloidal field‐reversed configuration is determined from excluded flux data, allowing an improved determination of the plasma dimensions. Only gross features of the external separatrix, with scale lengths comparable to the coil radius, can be resolved.

ISSN:0031-9171    

DOI:10.1063/1.863283

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The scaling relations for a traveling mirror magnetic compressor [P.M. Bellan, Phys. Rev. Lett. 43, 858 (1979)] having nonconstant capacitance are derived. Varying capacitance (rather than inductance) makes possible a lower impedance device, and hence, higher field levels or faster compression times.

ISSN:0031-9171    

DOI:10.1063/1.863284

出版商:AIP    

年代:1981

数据来源: AIP