1. Two-Stream Instability in Finite Beams
2. Oscillations of a Finite Cold Plasma in a Strong Magnetic Field
3. In deriving Eq. (49) we have assumed that there were two species with maximum plasma frequencies ωp01 and ωp02. For one of these V = 0. A plot of the left-hand side of Eq. (33) versus ω shows that if η is above the minimum of the curve there will be four real roots. If η is below the minimum two of the roots must be complex. The left-hand side of Eq. (49) is the minimum value of the right-hand side of Eq. (33).
4. P. M. Morse and H. Feshbach,Methods of Theoretical Physics(McGraw-Hill Book Company, Inc., New York, 1953), Vol. 2, p. 1101.