摘要:

A nonlinear dispersion equation for the spectrum of parametric instabilities is derived from the hydrodynamic equations. New resonant mode−coupling terms coming from ion and electron equations are found. Solution of the dispersion equation yields an oscillating two−stream spectrum which varies ask−2in agreement with computer simulations and a numerical solution.

ISSN:0031-9171    

DOI:10.1063/1.861111

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

An asymptotic expansion scheme is set up, which is appropriate to deal with the deviations from axisymmetry occurring in tokamaks and Ohmically heated stellarators. Solutions of the magnetohydrostatic equations are sought to all orders in the expansion parameter, which is related both to the magnitude of the deviations from axisymmetry and to the ratio of poloidal vs toroidal components of current and magnetic field. Arguments are presented for the existence of the solution to any finite order, the pressure and current profiles across the plasma column, in general, being determined by the nonaxisymmetric part of the external magnetic field. If the latter, however, has certain symmetries, then a degeneracy occurs, and the pressure and current profiles can again be given with some degree of arbitrariness. It is shown that for tokamaks and stellarators of standard design, viz., including the perturbations associated with the ’’ripples’’ in the toroidal field, the ’’gaps’’ in the copper shell, and the helical windings, the degree of arbitrariness in the pressure and current profiles is the same as in the axisymmetric theory. Thus, in such machines the above profiles are expected to be governed entirely by transport effects, a conclustion which is borne out by the experiments.

ISSN:0031-9171    

DOI:10.1063/1.861112

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Consistent approximation calls for taking into consideration the effect of inertia of the fluid in a pressure gradient thus canceling out the term due to static pressure alone. Inconsistency may lead to ill−posed formulations.

ISSN:0031-9171    

DOI:10.1063/1.861113

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

An exact aerodynamic noise equation is formulated for Newtonian fluids. The cause−effect problem is discussed. Finally, the importance of external additions of mass, momentum, and energy is examined.

ISSN:0031-9171    

DOI:10.1063/1.861114

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The decay of a circularly polarized electromagnetic wave propagating parallel to an external magnetic field into another circularly polarized electromagnetic wave and an ion acoustic wave in a homogeneous plasma is considered.

ISSN:0031-9171    

DOI:10.1063/1.861102

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

This theoretical study of ion wave echoes is based on a model which takes into consideration ion−atom collisions. It is found that the collision model gives a damping term varying with the collision frequency &ngr; as exp(−&ngr;t).

ISSN:0031-9171    

DOI:10.1063/1.861126

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The parametric decay instability of a large amplitude extraordinary pump wave into a whistler wave and a backscattered extraordinary wave is investigated by computer simulation.

ISSN:0031-9171    

DOI:10.1063/1.861127

出版商:AIP    

年代:1975

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.861129

出版商:AIP    

年代:1975

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.861099

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Stability of the force−free high−&bgr; plasma is considered. Comments on the deviation of the dispersion relations obtained for the highly unstable made are presented. (AIP).

ISSN:0031-9171    

DOI:10.1063/1.861100

出版商:AIP    

年代:1975

数据来源: AIP