@article{3fada401ff5c447ca7fd25fce0fb3bd0,
title = "Experimental Observation of Proton Bunch Modulation in a Plasma at Varying Plasma Densities",
abstract = "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 bunch. The modulation extends over the length of the proton bunch following the seed point. By varying the plasma density over one order of magnitude, we show that the modulation frequency scales with the expected dependence on the plasma density, i.e., it is equal to the plasma frequency, as expected from theory.",
author = "{AWAKE Collaboration} and E. Adli and A. Ahuja and O. Apsimon and R. Apsimon and Bachmann, {A. M.} and D. Barrientos and Barros, {M. M.} and J. Batkiewicz and F. Batsch and J. Bauche and {Berglyd Olsen}, {V. K.} and M. Bernardini and B. Biskup and A. Boccardi and T. Bogey and T. Bohl and C. Bracco and F. Braunm{\"u}ller and S. Burger and G. Burt and S. Bustamante and B. Buttensch{\"o}n and A. Caldwell and M. Cascella and J. Chappell and E. Chevallay and M. Chung and D. Cooke and H. Damerau and L. Deacon and Deubner, {L. H.} and A. Dexter and S. Doebert and J. Farmer and Fedosseev, {V. N.} and G. Fior and R. Fiorito and Fonseca, {R. A.} and F. Friebel and L. Garolfi and S. Gessner and I. Gorgisyan and Gorn, {A. A.} and E. Granados and O. Grulke and E. Gschwendtner and A. Guerrero and Y. Li and B. Williamson and G. Xia",
year = "2019",
doi = "10.1103/PhysRevLett.122.054802",
language = "English",
volume = "122",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "5",
}