Author: Gessner, S.J.
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TUPME050 Electron Bunch Self-modulation in Long Plasmas at SLAC FACET 1476
 
  • P. Muggli
    MPI, Muenchen, Germany
  • E. Adli, V.K.B. Olsen
    University of Oslo, Oslo, Norway
  • L.D. Amorim
    IST, Lisboa, Portugal
  • S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
    SLAC, Menlo Park, California, USA
  • C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
    UCLA, Los Angeles, California, USA
  • N.C. Lopes, J. Vieira
    Instituto Superior Tecnico, Lisbon, Portugal
  • O. Reimann
    MPI-P, München, Germany
 
  Funding: This work performed in part under DOE Contract DE-AC02-76SF00515.
We study the physics of self-modulation instability (SMI) of long, when compared to the wake wavelength, electron and positron bunches in pre-formed plasmas at SLAC-FACET. Self-modulation is the result of the action of focusing/defocusing transverse wakefields on the bunch radius. Self-modulation leads to observables such as overall defocusing of the bunch, periodic modulation of the bunch radius at the wake period and multi-GeV energy gain/loss by drive bunch particles. Defocusing is observed from OTR images, radial self-modulation from CTR spectra and interferometric traces and energy gain/loss from energy spectra with sub-GeV resolution. The plasma density is varied by changing the vapor density ionized by a laser/axicon system. The bunch length, radius and charge can also be varied. The SMI can be seeded using a notch collimator system. Numerical simulations indicate that seeding the SMI mitigates the hose instability. Hose instability can also be seeded, for example by using the RF deflecting cavity to impart a tilt to the incoming bunch axis. The overall experimental plan as well as the latest experimental results obtained with electron bunches will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME050  
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THPRI013 A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV 3791
 
  • J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • W. An, C. Joshi, W.B. Mori
    UCLA, Los Angeles, California, USA
 
  An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI013  
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