X-14: Ion Motion

Principle Investigator:

Contact in absentia:
Richard D'Arcy

Description and goals:
In a future beam driven plasma wakefield accelerator (PWFA) based linear collider beam emittance preservation is of great significance. High-density, low-emittance, high-energy particle bunches violate the approximation of a static ion background. With a non-uniform ion - density due to ion motion - the ion-based linear focusing fields are perturbed, ultimately leading to emittance growth.

In order to generate ion motion in PWFA the beam density must be  at least 2000 times larger than the plasma density, with a larger signal expected at ever higher beam and plasma densities. Due to these two factors it has been difficult to experimentally detect the emittance growth expected due to this ion motion. The FLASHForward X-14 experiment intends to experimentally demonstrate the effect of ion motion for the first time.