Conditions are determined for which the ions of a plasma might gain appreciable energy from the interaction with an electron beam. The waves along the magnetic field in a one-dimensional beam-plasma system are examined. For a cold plasma, the transverse waves exhibit a convective instability near the ion cyclotron frequency and a nonconvective instability at very low frequencies. The convective instability is greatly altered by a finite ion temperature, whereas the low frequency instability is relatively unaffected by temperature. For a weak beam, the longitudinal interaction occurs above the electron plasma frequency unless V/sub o/ T/sub e/, where V/sub o/ is the d-c beam voltage and T/sub e/ is the electron temperature. A very strong interaction at the ion plasma frequency arises if (n/sub b//n) (T/sub e//V/sub o/) 1, where n/sub b/ and n/sub p/ are the beam and plasma densities. For both transverse and longitudinal interactions it is shown that the presence of damping (cyclotron or Landau) can give rise to resistive medium type instabilities. Some brief results will also be given on the interactions in finite geometries which include the electron temperature. (auth).

This study considers the instabilities that result when an electron beam is injected into a plasma. A number of different models of the system are considered, and all instabilities are classified according to whether they are convective instabilities (amplifying waves) or nonconvective (absolute) instabilities. The study also analyzes the instabilities in unbounded beam-plasma systems and in systems of finite extent transverse to the electron stream and gives a detailed consideration of the possibility of a strong interaction with the ions in a hot-electron plasma. In addition, the author presents mathematical criteria for identifying absolute instabilities and amplifying waves. These criteria are based only on an analysis of the dispersion equation of the system and are not restricted to beam-plasma systems.Two things need to be said about this book: the chapter on absolute and convective instabilities makes an important contribution to the field. Second, it should be pointed out that the theoretical results are reduced to a form which make them readily available to an experimentalist. Plasma physicists and electronic engineers will be interested in this work.

The report suggests possible ways for further theoretical study of the interaction of an electron beam and the ions in a hot-electron plasma. Equations are obtained for beamplasma interaction in a filled cylindrical waveguide in which the thermal velocity distribution is longitudinal but otherwise arbitrary. An approximation is described based on these equations by using only one transverse wave number. A close resemblance is found between the approximate solutions and the theory of plane waves in an infinite beamplasma system, traveling at an angle with the direction of the beam and the magnetic field and having a certain fixed real transverse wave number. Advantage is taken of this resemblance to calculate beam- (hot-electron) plasma interaction including a transverse random velocity distribution. The theory of a filamentary beam is combined with that of a plasma-filled waveguide, using the coupling-of-modes theory, for the description of some of the weak interactions between a thin beam and a finite plasma. (Author).

Recent scientific and technical advances have made it possible to create matter in the laboratory under conditions relevant to astrophysical systems such as supernovae and black holes. These advances will also benefit inertial confinement fusion research and the nation's nuclear weapon's program. The report describes the major research facilities on which such high energy density conditions can be achieved and lists a number of key scientific questions about high energy density physics that can be addressed by this research. Several recommendations are presented that would facilitate the development of a comprehensive strategy for realizing these research opportunities.