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[en] The publishing house 'Avers' has published O.D. Volpyan's and A.I. Kuzmichev's book 'Negative Refraction of Waves'. (bibliography)

[en] The aim of this work is to find out to what extent the action of a gravitational wave on an elastic body can be treated exactly. The idea is not so much to calculate what happens under certain fairly ideal circumstances but to be able to check by comparison, the various methods of approximation which may have to be used

No abstract available

No abstract available

[en] Two Comments on the Letter by D. Mugnai, A. Ranfagni, and R. Ruggeri, Phys.Rev.Lett.84, 4830 (2000)

[en] The velocities of ultrasonic waves in a uniaxially compressed concrete are influenced by microcracking. The experimental results are commented and a model of propagation in a randomly microcracked medium is built. The model shows a high anisotropy of propagation when all cracks have the same orientation

[en] Excitation of streamers by modulationally unstable small-scale drift-Alfvén wave (SSDAW) is investigated. It is found that the excitation depends strongly on the propagation direction of the SSDAW, and the ion and electron diamagnetic drift waves are both unstable due to the generation of streamers. It is also shown that zonal flows can be effectively excited by the SSDAW with the propagation direction different from that for streamer excitation

[en] Observations of pulsating auroras with an all-sky Isocon TV system made from Poker Flat Research Range, Alaska, and Andoya rocket range, Norway, have revealed that auroral forms propagating like waves, (here termed recurrent propagating auroral forms) predominantly in the meridional direction, are a significant proportion of the group of auroras commonly labelled pulsating auroras. The wavelike forms are described and compared with pulsating patches. Characteristics of the two types differ sufficiently, that the possibility of different mechanisms should be considered. Propagation of the wave forms continues up to discrete arcs on the poleward edge of the diffuse aurora. One example is presented where no enhancement was observed within black aurora when the wave forms encountered this on their propagation path. (author)