Richard F. Post

Prospects for Fusion Power.

The quest for fusion power began some forty years ago, with the discovery of nuclear fusion reactions, followed by the theory of thermonuclear processes, which successfully explained the source of the energy of the Sun and stars. But then, apart from the musings of a perceptive few, nearly twenty years passed before heightened interest in nuclear energy sources stimulated a serious attack on the problem. By this time both the potentialities of fusion and the growing need for energy from other than fossil‐fuel sources had become apparent. Here I shall try to evaluate the present state of research on controlled thermonuclear reactions in the context of the urgent need for developing new, environmentally acceptable, energy sources.The quest for fusion power began some forty years ago, with the discovery of nuclear fusion reactions, followed by the theory of thermonuclear processes, which successfully explained the source of the energy of the Sun and stars. But then, apart from the musings of a perceptive few, nearly twenty years passed before heightened interest in nuclear energy sources stimulated a serious attack on the problem. By this time both the potentialities of fusion and the growing need for energy from other than fossil‐fuel sources had become apparent. Here I shall try to evaluate the present state of research on controlled thermonuclear reactions in the context of the urgent need for developing new, environmentally acceptable, energy sources.

The Propagation of Underwater Sound at Low Frequencies as a Function of the Acoustic Properties of the Bottom

The correlation and theoretical analysis of a large number of transmission measurements made in the Potomac River and Chesapeake Bay areas warrants the conclusions which follow. Given a source of audiofrequency sound in water, the sound pressure level which may be measured at appreciable distances will be influenced in a complicated way by the boundaries, especially by the bottom. The sea bottom may be classified by its behavior for sound as “soft,” “hard,” or intermediate in character. Specifically, the velocity of sound and the density of the bottom may be estimated from acoustic measurements (hydrophone soundings and range runs), by sampling, and from hydrographic data. The effect of the boundaries on sound propagation from a ship‐mounted source may be determined from an analysis of the normal modes of vibration of the acoustic system of the sea between surface and bottom. The analysis is particularly effective for frequencies at which the wave‐lengths are comparable to the physical dimensions of the s...