Telescoping Beams for Heavy Ion Fusion

In addition to the strong longitudinal compression and multiple beams now used in all designs for heavy ion fusion drivers, attaining the required beam power could be helped by telescoping bunches of different ion species. Telescoping is here defined as the overtaking and interpenetration of bunches consisting of ions of different species but whose velocity, mass, and charge state have been selected so that the typical ions in the various bunches have the same ratio of momentum to charge, or magnetic rigidity, and, therefore, the same single particle dynamics in transport and focussing lines. With velocities differing by 10% or more, the highest powers would only arise close to the end of the transport lines. Telescoping also increases the total available phase space of the different species. This can be translated to a smaller final momentum spread or a means to accommodate greater phase space dilution.