Passage of radiation through moving astrophysical plasmas

Journal Article · Thu Jun 15 00:00:00 EDT 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156219· OSTI ID:6684651

Ko, H C; Chuang, C W

We discuss the effect of the motion of a refracting medium on the direction of refracted rays, and its implication in astrophysics. It is assumed that, in its own rest frame, the medium is homogeneous, isotropic, lossless, and transparent. A pencil beam of quasi-monochromatic radiation is incident normally upon the surface of a medium moving at uniform velocity in the direction parallel to the surface. For a medium which has only frequency dispersion and satisfies the Landau and Lifshitz transparency condition, it is shown that the refracted beam cannot be bent toward the upstream direction whether the refractive index is greater or smaller than unity. For a cold isotropic plasma, the motion has no effect on the direction of the refracted beam which is normal to the surface. For a nonrelativistic, warm isotropic plasma which has spatial dispersion in addition to the frequency dispersion, the refracted beam is bent toward the upstream direction. However, the amount of bending is too small to play significant roles in astrophysical phenomena. These results disagree with the conclusions reached by earlier investigators. The causes for the discrepancy are discussed.Based on the wave kinematical and electrodynamical considerations, we have shown that for a plane, quasi-monochromatic wave propagating in moving homogeneous dispersive media of infinite extent, the direction of energy flow coincides with that of the group velocity, but not with that of the Poynting vector.

• Research Organization: Department of Electrical Engineering and Department of Astronomy, The Ohio State University
• OSTI ID: 6684651
• Journal Information: Astrophys. J.; (United States), Vol. 222:3
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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ISOTROPY
LANDAU DAMPING
POYNTING THEOREM
PULSARS
WAVE PACKETS
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