摘要:

A theory is presented describing mode conversion and tunneling in a warm, collisionless, toroidal plasma near the first ion‐cyclotron harmonic frequency when the waves are propagating perpendicular to the static magnetic field. The coupling region may be characterized by a fourth‐order differential equation with one turning point. Employing the method of Laplace integrals and the method of matched asymptotic expansions, transmission, reflection, and conversion coefficients are calculated assuming a fast wave is incident from either side of the coupling region. For a fast wave incident from the low magnetic field side, transmission, reflection, and conversion occur, while for a fast wave incident from the high magnetic field side, only transmission and conversion occur with no reflection, independent of the thickness of the tunneling layer, which implies complete conversion of the fast wave to the slow wave as the tunneling layer becomes thick. The problem of cavity resonance is discussed.

ISSN:0031-9171    

DOI:10.1063/1.861812

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The influence of strong self‐electric fields on the ion resonance instability is examined for a cylindrical nonneutral plasma column immersed in a uniform axial magnetic fieldB0eˆz. The analysis is carried out within the framework of a macroscopic cold‐fluid model, and electrostatic stability properties are investigated for the case of rectangular electron and ion density profiles. The parameter &dgr;= (2&ohgr;2pe/&ohgr;2ce)   (1−f) is introduced as a convenient measure of the relative strengths of the equilibrium self‐electric force and the magnetic force on an electron fluid element. (Here, &ohgr;⁁peis the electron plasma frequency, &ohgr;ceis the electron cyclotron frequency,f=n0i/n0eis the fractional charge neutralization, and &dgr;=1 corresponds to the maximum allowed charge density for radial confinement of the equilibrium configuration.) An important conclusion of this study is that the equilibrium self‐electric field can have a large influence on stability behavior. In particular, stability properties for &dgr;≲1 differ substantially from those obtained when &dgr;≪1. Moreover, for nonneutral plasma column with significant charge neutralization, it is found that the fundamental mode (l=1) is not the most unstable mode. Rather, higher harmonic perturbations have larger growth rates. However, in the limiting case wheref≪1 and &dgr;≪1, thel=1 mode can have the largest growth rate, which is consistent with the result previously obtained by Levy, Daugherty, and Buneman.

ISSN:0031-9171    

DOI:10.1063/1.861813

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Plasma simulation models have been developed which replicate the fundamental features of the convective and oscillating instability in the nonlinear weak beam regime. The oscillating instability is characterized in this regime by a randomly fluctuating electric field which is caused by the presence of a fresh, strong beam in a region of space in which the electric field is large. Nonlinear behavior of the background plasma need not be present during the production of the oscillating instability. The convective instability develops into a quasilinear quiescent state during its nonlinear evolution because the nonlinear behavior of the system is confined to a diffused beam.

ISSN:0031-9171    

DOI:10.1063/1.861814

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Steady two‐dimensional flow between two eccentric rotating circular cylinders is considered. The angular speed of an inner cylinder subject to zero net viscous torque is determined for small eccentricities and small Ekman numbers.

ISSN:0031-9171    

DOI:10.1063/1.861815

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Experimental data are presented indicating improved homogeneity and stability of the luminous plasma in a hard core &Vthgr;‐pinch device equipped with quartz end‐stopper disks.

ISSN:0031-9171    

DOI:10.1063/1.861816

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A cold gas blanket of density &rgr;1reduces the plasma outflow velocityu5because of the inertia of the cold gas and the establishment of an internal ablation front by absorption of powerW(watt/cm2).u5is calculated as function of &rgr;1andW.

ISSN:0031-9171    

DOI:10.1063/1.861817

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The radial equations for the poloidal Fourier components of a drift wave in a torus are solved by a numerical finite element method. It is shown that in the trapped electron regime the solutions are not localized by shear.

ISSN:0031-9171    

DOI:10.1063/1.861818

出版商:AIP    

年代:1977

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.861819

出版商:AIP    

年代:1977

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.861820

出版商:AIP    

年代:1977

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.861821

出版商:AIP    

年代:1977

数据来源: AIP