Ion stability in pulse electron beams

The area of existence and limiting density of an ion skeleton, combined by an electron beam with a circular cross section and a strip beam with a finite bunch train frequency, are estimated. It is shown that the maximum ion skeleton density does not exceed the average one over the beam density bunch sequenece period and decreases with the beam density increase. There exists the reduced beam density value depending on relative bunch length, above which no ion skeleton is confined. The minimum skeleton density for equal beam densities is attained in circular beams. 3 refs.; 1 fig