Related papers: Development of the Self-Modulation Instability of …
The self-modulation instability is a key effect that makes possible the usage of nowadays proton beams as drivers for plasma wakefield acceleration. Development of the instability in uniform plasmas and in plasmas with a small density…
A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing…
We study experimentally the longitudinal and transverse wakefields driven by a highly relativistic proton bunch during self-modulation in plasma. We show that the wakefields' growth and amplitude increase with increasing seed amplitude as…
We present numerical simulations and experimental results of the self-modulation of a long proton bunch in a plasma with linear density gradients along the beam path. Simulation results agree with the experimental results reported in…
An analytical model for the self-modulation instability of a long relativistic proton bunch propagating in uniform plasmas is developed. The self-modulated proton bunch resonantly excites a large amplitude plasma wave (wake field), which…
The self-modulation (SM) instability transforms a long charged particle bunch traveling in plasma into a train of microbunches that resonantly drives large-amplitude wakefields. We present the first determination of the saturation length of…
We investigate numerically the detection of the self-modulation instability in a virtual detector located downstream from the plasma in the context of AWAKE. We show that the density structures, appearing in the temporally resolving virtual…
We show in experiments that a long, underdense, relativistic proton bunch propagating in plasma undergoes the oblique instability, that we observe as filamentation. We determine a threshold value for the ratio between the bunch transverse…
Seeded Self-modulation (SSM) has been demonstrated to transform a long proton bunch into many equidistant micro-bunches (e.g., the AWAKE case), which then resonantly excite strong wakefields. However, the wakefields in a uniform plasma…
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of a long proton bunch in plasma. We show experimentally that, with sufficient initial amplitude ($\ge(4.1\pm0.4)$…
We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of $2.1\times10^{14}$ and \unit[$7.7\times10^{14}$]{electrons/cm$^3$}. We show that these wakefields periodically defocus the…
We study experimentally the effect of linear plasma density gradients on the self-modulation of a 400\,GeV proton bunch. Results show that a positive/negative gradient in/decreases the number of micro-bunches and the relative charge per…
The AWAKE experiment relies on the self-modulation instability of a long proton bunch to effectively drive wakefields and accelerate an electron bunch to GeV-level energies. During the first experimental run (2016-2018) the instability was…
Seeded self-modulation in a plasma can transform a long proton beam into a train of micro-bunches that can excite a strong wakefield over long distances, but this needs the plasma to have a certain density profile with a short-scale ramp…
Effects of plasma inhomogeneity on self-modulating proton bunches and accelerated electrons were studied numerically. The main effect is the change of the wakefield wavelength which results in phase shifts and loss of accelerated particles.…
The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become…
We show in experiments that a long, relativistic proton bunch is focused by the plasma adiabatic response. The free plasma electrons migrate so as to neutralize the space charge field of the bunch, and the bunch is therefore focused by the…
In plasma wakefield accelerators (e.g. AWAKE) the proton bunch self-modulation is seeded by the ionization front of a high-power laser pulse ionizing a vapour and by the resulting steep edge of the driving bunch profile inside the created…
We study the evolution of the self-modulation instability using bunches with finite rise times. Using particle-in-cell simulations we show that unlike long bunches with sharp rise times, there are large variations of the wake amplitudes and…
AWAKE, the Advanced Proton-Driven Plasma Wakefield Acceleration Experiment, is a proof-of-principle R&D experiment at CERN using a 400 GeV/c proton beam from the CERN SPS (longitudinal beam size sigma_z = 12 cm) which will be sent into a 10…