Experimental, theoretical, and numerical investigation of the homogenization of density nonuniformities in the periodic transport of a space-charge dominated beam

The homogenization of a beam with a transversely nonuniform initial density distribution is examined by masking the ouput from a Pierce electron gun into five parallel beamlets, which are then propagated down a channel of periodically spaced solenoid focusing magnets. Experimental measurements, theoretical predictions, and PIC simulations are in excellent agreement for averaged beam quantities such as rms emittance and envelope radius. In addition, the fine-structure characteristic of the nonlinear evolution of the beam, including the formation of downstream images, is reproduced in detail by the simulations.