BASIC DATA OF PLASMA PHYSICS.

By Sanborn C. Brown '35. Cambridge: Technology Press; and New York: John Wiley,1959. 336 PP. $6.56.

Participants in a popular parlor game habitually attempt to file everything in one of three pigeonholes labeled animal, vegetable, and mineral. An equally good filing system which would have enlisted, until comparatively recently, the support of most physicists would have left the number of pigeonholes unchanged but labeled them with the three ordinary states of matter: liquid, solid gaseous.

The physicist of today would have to add a pigeonhole, one which would be far, far bigger than the other three combined, in fact, so vast that it would contain most of the universe. The label on this slot would be that of the "fourth state of matter," the plasma state. Stars, including our sun, are plasma, by which is meant that they are made up of exceedingly hot, wholly ionized gases consisting of charged nuclei and electrons in very rapid random motion.

A great deal of current interest in plasma physics has been due to the belief that an extremely hot plasma, if properly confined, can result in a controlled thermonuclear re- action. That is, if the charged nuclei in the plasma can be made hot enough, they will be likely to fuse into new particles on collision, releasing enormous quantities of energy in the process. To confine and sustain such a reaction is the goal of physicists the world over.

Professor Brown's book is a compilation of data, usually in the form of graphs and tables, carefully collected and handsomely displayed. The book is a result of the com- bination of the class notes for a graduate course in gas discharges given by Professor Brown at the Massachusetts Institute of Technology and the current Basic Data of Electrical Discharges, a technical report of the M.I.T. Research Laboratory of Electronics.

This is the first time that much of this material has been available in book form. It is indeed true that a complete understanding of the material in this book would be necessary for anyone engaged in plasma physics, but it is also true that this is not a book for the layman.