Title: Space charge limiting of bounded relativistic electron beams

Collective methods of ion acceleration using intense relativistic electron beams (IREB) have stimulated a great deal of interest in the past few years. The main virtue of an IREB collective ion accelerator is the high internal electric field strength. The primary drawback has been an insufficient ion energy gain or inadequate scaleability. An extensive study for generating a high quality electron beam has been done and is presented in Section II. In Section III an intense ion injector study was conducted by the method of computer simulation. The last addition to the proposal was a design for producing a toroidalmore » magnetic field. This field will be needed in a future study of high energy and high current electron beams.« less

A relativistic particle-in-cell simulation code has been used to study the space-charge limiting currents of a solid and an annular relativistic electron beam. The resulting limiting currents are significantly higher than that given by the widely used Bogdankevich--Rukhadze interpolation formula.

Beginning with the Green function for a rod beam in a round beam pipe we derive the space charge induced average energy change and rms spread for relativistic beams that are slowly converging or diverging in round beam pipes, a result that tends to be much larger than the 1/{gamma}{sup 2} dependence for parallel beams. Our results allow for beams with longitudinal-transverse correlation, and for slow variations in beam pipe radius. We calculate, in addition, the space charge component of energy change and spread in a chicane compressor. This component indicates source regions of coherent synchrotron radiation (CSR) energy changemore » in systems with compression. We find that this component, at the end of example compressors, approximates the total induced voltage obtained by more detailed CSR calculations. Our results depend on beam pipe radius (although only weakly) whereas CSR calculations do not normally include this parameter, suggesting that results of such calculations, for systems with beam pipes, are not complete.« less

>The space charge waves of the Gaussian beam were studied. Space charge wavelengths, and thereby the plasma frequency reduction coefficients, were calculated. The physical problem is stated in equations. The general theory of the second order linear differential equations was applied and approximate solutions were constructed. The Gaussian beam was compared with the homogeneous beam and a beam with density varying as 1/r. A rigorous formulation is presented for the integral equation of traveling wave tubes with electron beams of arbitrary cross section. It is shown that the integral equations have general applicability in electron beam-structure interaction studies. A bibliographymore » is included. (M.C.G.)« less

The possibility of observing the coherent visible radiation generation by using the particle beam at Lawrence Berkeley Laboratory, which passes through a solid space-periodic target, is considered. The estimations for parameters of such a system and the geometry of a possible experiment is analyzed.