Plasma wakefield accelerators using a long particle bunch as driver rely on a self-modulation process transversely modulating the long bunch into micro bunches that resonantly drive the wakefields [1]. Seeding the self-modulation at a level exceeding the noise level suppresses possible competing instabilities such as the hosing instability and leads to a phase reproducible modulation, needed...
The AWAKE Experiment at CERN relies on the Seeded Self-Modulation (SSM) process, which transversely modulates the charge density of the SPS proton bunch and turns it into a train of micro-bunches. While the SSM process is axi-symmetric, the hosing instability (HI) is non-axi-symmetric and can grow from bunch or plasma axial asymmetries. As the growth rates of the Self-Modulation Instability...
Plasma accelerators have great potential to form the basis of the next generation of compact linear colliders or FELs. Along with the high accelerating gradients inherent to plasma devices, another key requirement for such future machines is high beam quality—low emittance and low energy spread. The FLASHForward X-1 experiment is aimed at demonstrating the generation and subsequent...
Fundamental improvements of the quality, and stability of the electron output of plasma wakefield accelerators are required to realize key applications such as hard X-ray FELs and lepton colliders [1]. Here we report on the first realization of a plasma photocathode [2], in which a spatiotemporally synchronized laser beam is used to release tunnel-ionized electrons inside an electron beam...
