Plasma-physical aspects of charged-particle beams

Areas of interest for charged-particle beams are mentioned, and the classical beam concepts due to Alfv\'en, Lawson, and Bennett are described. From the equation of plasma mass transport the virial theorem of plasma physics is derived and evaluated for rotationally symmetric configurations so as to apply to long particle beams of nonrelativistic plasma character. A general global equation for such a beam expansion or compression is obtained and discussed. New aspects are given on the classical concepts, and the Alfv\'en-Lawson limiting current is slightly modified. With respect to certain important electron-beam properties observed in fusion research, special consideration is given to beam internal magnetic field generation and beam transverse mass rotation, and an important conversion mechanism is described.