摘要:

The filamentation instability of electromagnetic electron and ion‐cyclotron waves is investigated by including the combined effect of relativistic electron mass variation as well as static density and field‐aligned magnetic field perturbations that are created by the radiation pressure. Analytical expressions for the critical power at which the instability starts are presented. The relevance of this investigation to radio‐frequency wave heating of fusion plasmas is pointed out.

ISSN:0899-8221    

DOI:10.1063/1.858924

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A phenomenological treatment of the inertial range of isotropic statistically steady magnetohydrodynamic turbulence is presented, extending the theory of Kraichnan [Phys. Fluids8, 1385 (1965)]. The role of Alfve´n wave propagation is treated on equal footing with nonlinear convection, leading to a simple generalization of the relations between the times characteristic of wave propagation, convection, energy transfer, and decay of triple correlations. The theory leads to a closed‐form steady inertial range spectral law that reduces to the Kraichnan and Kolmogorov laws in appropriate limits. The Kraichnan constant is found to be related in a simple way to the Kolmogorov constant; for typical values of the latter constant, the former has values in the range 1.22–1.87. Estimates of the time scale associated with spectral transfer of energy also emerge from the new approach, generalizing previously presented ‘‘golden rules’’ for relating the spectral transfer time scale to the Alfve´n and eddy‐turnover time scales.

ISSN:0899-8221    

DOI:10.1063/1.859110

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The particle transport arising from the convection of nonadiabatic electron density by ion temperature gradient driven turbulence is examined for trapped electron collisionality regimes. In the lower temperature end of this regime, trapped electrons are collisional and the particle flux is outward ( in the direction of the gradients). When the trapped electrons are collisionless, there is a temperature threshold above which the electron temperature gradient driven particle flux changes sign and becomes inward. The magnitude of the nonadiabatic electron contribution to the growth rate is found to be potentially of the same order as the ion contribution.

ISSN:0899-8221    

DOI:10.1063/1.859111

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Detailed quasilinear trapped electron transport expressions are compared with the simple scaling forms of the extreme dissipative regime used in recent modeling studies. The problem of obtaining a consistent plasma pinch in the dissipative regime is discussed.

ISSN:0899-8221    

DOI:10.1063/1.859112

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The ordinary mode damping near the electron‐cyclotron frequency is investigated using the relativistic dispersion relation. It is shown that the Doppler splitting of the absorption spectrum claimed by Arunasalametal. [Phys. Rev. A36, 3909 (1987);37, 2063 (1988)] is an erroneous result obtained from an oversimplified dispersion relation and assuming an infinite speed of light in the resonance condition.

ISSN:0899-8221    

DOI:10.1063/1.859113

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A relativistic two‐fluid theory of linear surface waves propagating along the density and/or temperature discontinuity within a relativistic plasma has been developed. The effect of relativistic temperatures can be described by an increase of the effective particle mass by a factor proportional to the enthalpy per unit rest mass. As the electron temperature increases, the surface wave frequency spectrum is downshifted and shrinks and the contribution of the ion component to the dispersion properties becomes increasingly pronounced. In addition to the ‘‘standard’’ situation in the theory of surface waves when one deals with a density discontinuity, now a surface wave‐type solution formally exists even in a homogeneous plasma containing a temperature discontinuity.

ISSN:0899-8221    

DOI:10.1063/1.859114

出版商:AIP    

年代:1989

数据来源: AIP