Relaxation of a high-current relativistic beam in a plasma

The transport of a relativistic electron beam with an energy of 0.6--0.7 MeV and a current of 30 kA over a distance of 300 cm in a neutral gas has been studied. The beam transport is found to be accompanied by conspicuous changes in the beam distribution function, by intense microwave and x-ray emission, and by the appearance of a group of particles in the plasma with energies up to 25 keV. The modulation of the beam by collective fields was studied experimentally. The beam loss and the loss mechanism were determined.