Physics sense of ν/γ parameter in intense relativistic electron beam

ν/γ is an important physical parameter. ν，γ, are the Budker parameter and the relativistic mass factor, respectively. In this paper, its basic physical sense is expounded from three aspects of Lawson and Humphries formula and energy storage in intense relativistic electron beam. It can be expressed as the ratio of transverse electro-magnetic energy in the beam to its axial motion kinetic energy. For ν/γ closed to or greater than 1, there is an important self field effect in intense relativistic electron beam transport.