Emittance Growth of High Current Beams in Transport Lines

The rms emittance increase of high current beams in transport lines, caused by nonlinear space charge forces, can be understood as the development of the initial particle distribution to an equilibrium one. For a small beam radius, we get less rms emittance increase and the equilibrium distribution is reached earlier than for a large beam radius. The beam can now be transported over a long distance without further rms emittance growth in all 3 directions. These results are incorporated in the design of a funneling section for the high current linear accelerator of the HIBALL concept.