Abstract
One dimensional nonlinear evolution and localized structure of a high frequency beam mode were experimentally studied. Test waves were first linearly unstable, but stabilized in the nonlinear stage. The wave envelope behaved such as ki sech [ki(z-zo)] as a function of position z along the beam path, where ki is the linear growth rate. The results are discussed by a nonlinear theory on unstable beam waves in an electron beam plasma.
