摘要:

Nonlinear effects on the stationary equilibrium of spheroidal low‐aspect‐ratio plasma shapes with vacuum boundaries are considered mainly using appropriate linear methods. Simple analyses of both magnetohydrodynamic and guiding center fluids with anisotropic pressuresp⊥andp∥nearly equal to the scalar pressurepare presented. Results concerning the necessary amount of axial currentI0required for equilibrium are given and their implications for stability are described.

ISSN:0031-9171    

DOI:10.1063/1.862497

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The response of an axisymmetric toroidal tokamak plasma to first‐order particle and momentum sources is investigated. The momentum sources drive coupled poloidal and toroidal mass flows and electrostatic field evolution which relax to asymptotic values on a time scale characteristic of the dominant viscous or external drag mechanism. The asymptotic steady‐state momentum balance provides the necessary condition to completely determine the ambipolar potential, the particle fluxes, and currents in the flux surfaces and, hence, to determine transport fluxes across flux surfaces. Transport fluxes are driven across flux surfaces both by interspecies collisional momentum exchange, the usual case, and by momentum exchange between the plasma and external sources and/or drags. A generalized Ohm’s law is obtained and used to determine how particle and momentum sources drive parallel currents and alter the evolution of theqprofile. The theory is formulated for arbitrary plasma cross sections, beta, and collision regimes.

ISSN:0031-9171    

DOI:10.1063/1.862498

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The effects of the stellarator field on the positional stability of tokamak plasmas has been studied experimentally. The semi‐stellarator field can be substituted for the vertical field and significantly improves the stability of a tokamak plasma.

ISSN:0031-9171    

DOI:10.1063/1.862499

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Recently, collisionless drift waves in sheared magnetic fields were shown to be stable. The validity of the analytic model employed in one of these investigations is examined in detail.

ISSN:0031-9171    

DOI:10.1063/1.862500

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Gold disks have been irradiated with 1.06 &mgr;m laser light at intensities between 7 × 1013and 3 × 1015W/cm2, and pulse lengths between 200 and 1000 psec. Due to the highZand long pulse, inverse bremsstrahlung becomes an important absorption mechanism and competes strongly with resonance absorption and stimulated scattering. In addition to measured absorptions, data on the temporal, spatial, angular, and spectral characteristics of the x‐ray emission are presented. Temporally and spectrally resolved back‐reflected light, and polarization‐dependent sidescattered light are detected, providing estimates for the amount of stimulated scattering and of the coronal electron temperature. Inhibited electron thermal conduction and nonlocal thermodynamic equilibrium ionization physics play key roles in bringing numerical simulations of these experiments into agreement with all of the above‐mentioned data.

ISSN:0031-9171    

DOI:10.1063/1.862501

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An equation for invariant curves in the motion of a vortex blotch is derived. Kirchhoff’s elliptical vortex is shown to satisfy the equation. It is also found that small but finite harmonic derivations from a circular vortex are themselves steady motions.

ISSN:0031-9171    

DOI:10.1063/1.862502

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The Kramers–Giesekus stress tensor is shown to be incompatible with an Oldroyd time derivative in the evolution equation of polymer deformation.

ISSN:0031-9171    

DOI:10.1063/1.862503

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A model for one‐dimensional, zero‐slip, two‐phase flow through a Faraday magnetohydrodynamic generator is developed and used to determine the variation in duct cross section as a function of entrance conditions and load factor for uniform power output and velocity along the duct.

ISSN:0031-9171    

DOI:10.1063/1.862468

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Solitary ion acoustic waves in a magnetoplasma have been studied by Shukla and Yu [J. Math. Phys. 19, 2506 (1978)]. A more rigorous study confirms the conditions that Shukla and Yu said would be necessary for humps. However, it is shown that a density cavity is also possible in the limiting case.

ISSN:0031-9171    

DOI:10.1063/1.862469

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The nonlinear evolution of a bump‐on‐tail Maxwellian distribution function, to an initially unstable perturbation, is studied numerically. The results indicate that the time asymptotic solution is a Bernstein–Greene–Kruskal equilibrium.

ISSN:0031-9171    

DOI:10.1063/1.862470

出版商:AIP    

年代:1979

数据来源: AIP