Shaping of intense ion beams into hollow cylindrical form

A specifically tailored plasma lens could shape a high-energy, heavy-ion be am into the form of a hollow cylinder without loss of beam intensity. It ha s been experimentally confirmed that both a positive as well as a negative radial gradient of the current density in the active plasma lens can be the underlying principle. Calculations were performed that yield the ideal cur rent density distribution for both cases. A numerical simulation of an expe riment with an intense ion beam highlights that the shaping of the beam inc reases the achievable compression in a lead sample.