11 documents found, page 1 of 2
Experimental observation of the motion of ions in a resonantly driven plasma wa...
Turner, M.; Walter, E.; Amoedo, C.; Torrado, N.; Lopes, N.; Sublet, A.; Bergamaschi, M.; Pucek, J.; Mezger, J.; van Gils, N.; Verra, L.We show experimentally that an effect of motion of ions, observed in a plasma-based accelerator, depends inversely on the plasma ion mass. The effect appears within a single wakefield event and manifests itself as a bunch tail, occurring only when sufficient motion of ions suppresses wakefields. Wakefields are driven resonantly by multiple bunches, and simulation results indicate that the ponderomotive force ca...
Hosing of a long relativistic particle bunch in plasma
Nechaeva, T.; Verra, L.; Pucek, J.; Ranc, L.; Bergamaschi, M.; Della Porta, G. Z.; Muggli, P.; Agnello, R.; Ahdida, C. C.; Amoedo, C.; Andrebe, Y.Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, self-modulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on ...
Filamentation of a relativistic proton bunch in plasma
Verra, L.; Amoedo, C.; Torrado, N.; Clairembaud, A.; Mezger, J.; Pannell, F.; Pucek, J.; van Gils, N.; Bergamaschi, M.; Della Porta, G. Z.; Lopes, N.We show in experiments that a long, underdense, relativistic proton bunch propagating in plasma undergoes the oblique instability, which we observe as filamentation. We determine a threshold value for the ratio between the bunch transverse size and plasma skin depth for the instability to occur. At the threshold, the outcome of the experiment alternates between filamentation and self-modulation instability (evi...
Development of the self-modulation instability of a relativistic proton bunch i...
Verra, L.; Wyler, S.; Nechaeva,T.; Pucek, J.; Bencini, V.; Bergamaschi, M.; Velotti, F.; Della Porta, G. Z.; Gschwendtner, E.; Muggli, P.; Agnello, R.Self-modulation is a beam–plasma instability that is useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing the ratio between the initial transverse size of the bunch and the plasma skin depth, the instability occurs later along the bunch, or not at all, over a fixed plasma length because the amplitude of the ...
The AWAKE Run 2 Programme and beyond
Gschwendtner, E.; Lotov, K.; Muggli, P.; Wing, M.; Agnello, R.; Ahdida, C. C.; Gonçalves, M. C. A.; Andrebe, Y.; Apsimon, O.; Apsimon, R.Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use of high energy protons to drive wakefields in plasma has been demonstrated during Run 1 of the AWAKE programme at CERN. Protons of energy 400 GeV drove wakefields that accelerated electrons to 2 GeV in under 10 m of plasma. The AWAKE collaboration is now embarking on Run 2 with the main aims to demonstra...
Controlled growth of the self-modulation of a relativistic proton bunch in plasma
Verra, L.; Della Porta, G. V.; Pucek, J.; Nechaeva, T.; Wyler, S.; Bergamaschi, M.; Senes, E.; Guran, E. D.; Moody, J. T.; Kedves, M. Á.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 reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefi...
Simulation and experimental study of proton bunch self-modulation in plasma wit...
Morales Guzmán, P. I.; Muggli, P.; Agnello, R.; Ahdida, C. C.; Aladi, M.; Amoedo Goncalves, M. C.; Andrebe, Y.; Apsimon, O.; Apsimon, R.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 [F. Braunmller, T. Nechaeva et al. (AWAKE Collaboration), Phys. Rev. Lett. 125, 264801 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.264801]: with negative gradients, the charge of the...
Analysis of proton bunch parameters in the AWAKE experiment
Hafych, V.; Caldwell, A.; Agnello, R.; Ahdida, C. C.; Aladi, M.; Amoedo Goncalves, M. C.; Andrebe, Y.; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.A precise characterization of the incoming proton bunch parameters is required to accurately simulate the self-modulation process in the Advanced Wakefield Experiment (AWAKE). This paper presents an analysis of the parameters of the incoming proton bunches used in the later stages of the AWAKE Run 1 data-taking period. The transverse structure of the bunch is observed at multiple positions along the beamline us...
Experimental study of extended timescale dynamics of a plasma wakefield driven ...
Chappell, J.; Adli, E.; Agnello, R.; Aladi, M.; Andrebe, Y; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.; Baistrukov, M. A.; Batsch, F.; Bergamaschi, M.Plasma wakefield dynamics over timescales up to 800 ps, approximately 100 plasma periods, are studied experimentally at the Advanced Wakefield Experiment (AWAKE). The development of the longitudinal wakefield amplitude driven by a self-modulated proton bunch is measured using the external injection of witness electrons that sample the fields. In simulation, resonant excitation of the wakefield causes plasma ele...
Proton beam defocusing in AWAKE: comparison of simulations and measurements
Gorn, A.; Turner, M.; Adli, E; Agnello, R.; Aladi, M.; Andrebe, Y.; Apsimon, O.; Apsimon, R.; Bachmann, A. -M.; Baistrukov, M. A.; Batsch, F.In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from the Super Proton Synchrotron at CERN. The angular distribution of the protons deflected due to SSM is a quantitative measure of the process, which agrees with simulations by the two-dimensional (axisymmetric) particle-in-cell code LCODE to about 5%. The agreement is achieved in beam population scans at two selected plasma...