TY - JOUR

T1 - Dissipation of electron-beam-driven plasma wakes

AU - Zgadzaj, Rafal

AU - Silva, T.

AU - Khudyakov, V. K.

AU - Sosedkin, A.

AU - Allen, J.

AU - Gessner, S.

AU - Li, Zhengyan

AU - Litos, M.

AU - Vieira, J.

AU - Lotov, K. V.

AU - Hogan, M. J.

AU - Yakimenko, V.

AU - Downer, M. C.

PY - 2020/12/1

Y1 - 2020/12/1

N2 - Metre-scale plasma wakefield accelerators have imparted energy gain approaching 10 gigaelectronvolts to single nano-Coulomb electron bunches. To reach useful average currents, however, the enormous energy density that the driver deposits into the wake must be removed efficiently between shots. Yet mechanisms by which wakes dissipate their energy into surrounding plasma remain poorly understood. Here, we report picosecond-time-resolved, grazing-angle optical shadowgraphic measurements and large-scale particle-in-cell simulations of ion channels emerging from broken wakes that electron bunches from the SLAC linac generate in tenuous lithium plasma. Measurements show the channel boundary expands radially at 1 million metres-per-second for over a nanosecond. Simulations show that ions and electrons that the original wake propels outward, carrying 90 percent of its energy, drive this expansion by impact-ionizing surrounding neutral lithium. The results provide a basis for understanding global thermodynamics of multi-GeV plasma accelerators, which underlie their viability for applications demanding high average beam current.

AB - Metre-scale plasma wakefield accelerators have imparted energy gain approaching 10 gigaelectronvolts to single nano-Coulomb electron bunches. To reach useful average currents, however, the enormous energy density that the driver deposits into the wake must be removed efficiently between shots. Yet mechanisms by which wakes dissipate their energy into surrounding plasma remain poorly understood. Here, we report picosecond-time-resolved, grazing-angle optical shadowgraphic measurements and large-scale particle-in-cell simulations of ion channels emerging from broken wakes that electron bunches from the SLAC linac generate in tenuous lithium plasma. Measurements show the channel boundary expands radially at 1 million metres-per-second for over a nanosecond. Simulations show that ions and electrons that the original wake propels outward, carrying 90 percent of its energy, drive this expansion by impact-ionizing surrounding neutral lithium. The results provide a basis for understanding global thermodynamics of multi-GeV plasma accelerators, which underlie their viability for applications demanding high average beam current.

KW - ACCELERATION

KW - GENERATION

KW - IONIZATION

UR - http://www.scopus.com/inward/record.url?scp=85091290995&partnerID=8YFLogxK

U2 - 10.1038/s41467-020-18490-w

DO - 10.1038/s41467-020-18490-w

M3 - Article

C2 - 32958741

AN - SCOPUS:85091290995

VL - 11

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

IS - 1

M1 - 4753

ER -