7 documents found, page 1 of 1
Transition between instability and seeded self-modulation of a relativistic par...
Batsch, F.; Muggli, P.; Agnello, R.; Ahdida, C. C.; Amoedo Goncalves, M. C.; Andrebe, Y.; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.; Baistrukov, M. A.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 [≥(4.1±0.4) MV/m], the phase of the modulation along the bunch is reproducible from event to event, with 3%-7% (of 2?) rms variations all along the bunch. The phase is not reproducible for lower ...
Proton bunch self-modulation in plasma with density gradient
Braunmuller, F.; Nechaeva, T.; Adli, E.; Agnello, R.; Aladi, M.; Andrebe, Y.; Apsimon, O.; Apsimon, R.; Bachmann, A. -M.; Baistrukov, M. A.; Batsch, F.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 or negative gradient increases or decreases the number of microbunches and the relative charge per microbunch observed after 10 m of plasma. The measured modulation frequency also increases or decreases. With the largest positive gradient we observe two frequencies...
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...
Experimental study of wakefields driven by a self-modulating proton bunch in pl...
Turner, M.; Muggli, P.; Adli, E.; Agnello, R.; Aladi, M.; Andrebe, Y.; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.; Baistrukov, M. A.; Batsch, F.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 well as with the proton bunch charge in the plasma. We study transverse wakefields using the maximum radius of the proton bunch distribution measured on a screen downstream fr...
Experimental observation of plasma wakefield growth driven by the seeded self-m...
Turner, M.; Adli, E.; Ahuja, A.; Apsimon, O.; Apsimon, R.; Bachmann, A. -M.; Barros, M. M.; Barrientos, D.; Batsch, F.; Batkiewicz, J.; Bauche, J.We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1×10^14 and 7.7×10^14 electrons/cm^3. We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time...
Experimental observation of proton bunch modulation in a plasma at varying plas...
Adli, E.; Ahuja, A.; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.; Barrientos, D.; Barros, M. M.; Batkiewicz, J.; Batsch, F.; Bauche, J.We give direct experimental evidence for the observation of the full transverse self-modulation of a long, relativistic proton bunch propagating through a dense plasma. The bunch exits the plasma with a periodic density modulation resulting from radial wakefield effects. We show that the modulation is seeded by a relativistic ionization front created using an intense laser pulse copropagating with the proton bu...
Acceleration of electrons in the plasma wakefield of a proton bunch
Adli, E.; Ahuja, A.; Apsimon, O.; Apsimon, R.; Bachmann, A.-M.; Barrientos, D.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bohl, T.High-energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. To increase the energy of the particles or to reduce the size of the accelerator, new acceleration schemes need to be developed. Plasma wakefield acceleration(1-5), in which the electrons in a plasma are excited, leading to strong electric fields (so cal...