RELATIVISTIC ELECTRON-BEAM GENERATION IN A PLASMA-FILLED DIODE WITH FOILLESS INJECTION INTO A DENSE-PLASMA

In the experiments on relativistic electron beam (REB)-plasma interact ion, the foilless injection of REB from a magnetized diode is of speci al interest due to the low spread angle of the beam and high repetitio n rate of the shots. In the experiments presented, the problem of diod e shortening in the presence of a dense plasma from the interaction ch amber has been solved using a special drift pipe as an anode of the fo illess diode. The electron beam (U-d similar to 0.7 MeV, t(b) similar to 100-200 ns) produced by an axially symmetric magnetically insulated diode has been injected into a magnetized hydrogen plasma column with density ranging from 1 . 10(15)-3 . 10(16) cm(-3). It has been found that the anode pipe substantially reduces the plasma flow into the dio de gap, but does not stop it completely, thus the REB generation in a plasma-filled diode has taken place. In some regimes of the beam gener ation it becomes possible to increase significantly the injected curre nt and total energy deposition of the beam in comparison with the case of a vacuum magnetized diode of the same geometry. The experiments ha ve shown effective dense plasma heating under the foilless injection.