摘要:

The confinement properties of translating field‐reversed configurations (FRC) in the FRX‐C/T device [Phys. Fluids29, ▪ ▪ ▪ ▪ (1986)] are analyzed and compared to previous data without translation and to available theory. Translation dynamics do not appear to appreciably modify the FRC confinement. Some empirical scaling laws with respect to various plasma parameters are extracted from the data. These are qualitatively similar to those obtained in the TRX‐1 device [Phys. Fluids28, 888 (1985)] without translation and with a different formation method. Translation with a static gas fill offers new opportunities such as improved particle confinement or refueling of the FRC particle inventory.

ISSN:0031-9171    

DOI:10.1063/1.865888

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A nearly spherical field‐reversed configuration (FRC) is created by employing a combination of a double‐cusp bias magnetic field and laser‐produced plasma, and its plasma stability is studied. The FRC equilibrium configuration is found to last for 20–25 &mgr;sec, which is not determined by any plasma instability in the present experiment and is estimated to be longer than the Alfve´n time by a factor of more than 40. That is, the occurrence of neither then=2 rotational instability nor the active magnetohydrodynamic (MHD) (tilting) mode is observed during this time period. The stabilization of the rotational mode may be attributed to the effect of magnetic field line bending. Although the exact reason for stabilizing the tilting mode is not known, it has become clear that the geometry of an equilibrium FRC has no significant effect on its stability, based upon comparison with the other experimental results obtained thus far from theta‐pinch‐based FRCs with a very elongated cross section. It is suggested that the ion kinetic, nonadiabatic effect may be largely responsible for this stability.

ISSN:0031-9171    

DOI:10.1063/1.865889

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A nonlinear diffusion equation with a diffusion coefficient depending on the number density of diffusing particles affected by gravity is solved approximately for a stationary state. As a result, expectation values of both the number density and its position are estimated to explain the shifts from a linear diffusion system in conventional theories.

ISSN:0031-9171    

DOI:10.1063/1.865890

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It is shown that the generalized equation of state of a warm relativistic electron fluid reduces in the small‐m/elimit to the well‐known double adiabatic law of collisionless magnetohydrodynamics.

ISSN:0031-9171    

DOI:10.1063/1.865891

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Making use of the ideal magnetohydrodynamics, a set of coupled equations is derived which governs the dynamics of nonlinear ballooning modes. Criteria for the existence of a class of ballooning dipole vortices are presented.

ISSN:0031-9171    

DOI:10.1063/1.865892

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Accounting for an inhomogeneous magnetic field and finite Larmor radius effects, a set of nonlinear mode coupling equations is derived for finite amplitude drift waves in plasmas. It is shown that the present nonlinear equations admit localized dipole vortices. Conditions for the existence of these vortices are given.

ISSN:0031-9171    

DOI:10.1063/1.865893

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A kinetic model for generating lower‐hybrid waves by a low‐density, superthermal ion beam directed across a magnetic field is investigated. Growth rate calculations demonstrate the salient features of the process, in particular, the small threshold drift of several background ion thermal speeds required for instability. The mechanism is suitable for collisionless dissipation in systems which evince the characteristics of anomalous resistivity in the presence of relatively small electrical currents.

ISSN:0031-9171    

DOI:10.1063/1.865894

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Nonlinear bidirectional shallow water waves are shown to be described by a regularized long‐wave equation. Six constants of motion for this equation are exhibited.

ISSN:0031-9171    

DOI:10.1063/1.865895

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Injection of radio‐frequency power at twice the lower hybrid frequency results in parametric decay of the pump wave into electrostatic ion‐cyclotron modes. The location of the conversion point is inferred from the data.

ISSN:0031-9171    

DOI:10.1063/1.865896

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It is shown that magnetohydrodynamic (MHD) equilibria with reflectional symmetry and an internalm=1 island are either marginally stable or unstable if they possess a helical symmetry with a pitch length much larger than their radius.

ISSN:0031-9171    

DOI:10.1063/1.865897

出版商:AIP    

年代:1986

数据来源: AIP