Sep 24 – 30, 2017
La Biodola, Isola d'Elba
Europe/Rome timezone

Plasma-based diagnostic for the SMI in AWAKE

Sep 27, 2017, 7:30 PM
Parking Area, Hotel Hermitage

Parking Area, Hotel Hermitage

poster WG5 - High-Gradient Plasma Structures/Advanced Beam Diagnostics Wine and Poster Session 2 (WG4-WG5-WG6-WG7)


Ms Anna-Maria Bachmann (CERN)


AWAKE develops a new plasma wakefield accelerator using the CERN SPS proton bunch as a driver. The proton bunch propagates through a 10m long rubidium plasma, induced by an ionizing laser pulse that also seeds the wakefields for the self-modulation instability (SMI). Current diagnostics for the occurrence of the SMI focus on the proton bunch. The SMI transforms the bunch in a train with hundreds of bunchlets driving hundreds of plasma wave periods. We therefore investigate the possibility of measuring frequency modulation of a CW laser propagating perpendicularly to the wakefields to determine some of the wakefields characteristics. Wakefields period information will appear in the position of satellites in the laser beam spectrum, whereas wakefields amplitude information will be in the satellites intensity. Satellites at the harmonics of the plasma period would indicate nonlinear modulation of the plasma density and wakefields amplitude. Measuring the wakefields amplitude at two points of the plasma cell, near the plasma entrance and near the exit, would provide proof of the growth of the SMI.

Primary author

Ms Anna-Maria Bachmann (CERN)


Prof. Patric Muggli (Max-Planck-Institut für Physik)

Presentation materials