Author: Vieira, J.
Paper Title Page
TUPEA045 Self-Modulation and Hosing Instability of Slac Electron and Positron Bunches in Plasmas 1235
 
  • J. Vieira, N.C. Lopes
    Instituto Superior Tecnico, Lisbon, Portugal
  • E. Adli, S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
    SLAC, Menlo Park, California, USA
  • Y. Fang
    USC, Los Angeles, California, USA
  • C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
    UCLA, Los Angeles, California, USA
  • P. Muggli
    MPI, Muenchen, Germany
  • O. Reimann
    MPI-P, München, Germany
  • L.O. Silva
    IPFN, Lisbon, Portugal
  
  Funding: This work has been partially supported by Humboldt Foundation.
The un­der­stand­ing of the self-mod­u­la­tion (SMI) and hos­ing (HI) in­sta­bil­i­ties is crit­i­cal for the suc­cess of the up­com­ing pro­ton dri­ven plasma wake­field ac­cel­er­a­tion ex­per­i­ments at CERN*. The use of long SLAC elec­tron and positron bunches pro­vides the pos­si­bil­ity of un­der­stand­ing ex­per­i­men­tally the in­ter­play be­tween SMI and HI. In this work we per­form par­ti­cle-in-cell sim­u­la­tions with the code OSIRIS with pa­ra­me­ters that will be avail­able for ex­per­i­ments at SLAC in 2013. We show that the SMI of 20 GeV lep­ton bunches can grow and sat­u­rate in less than 15 cm. Up to 8 GeV en­ergy gain/loss could be ob­served after a meter long plasma. The HI can also be ef­fec­tively mit­i­gated by seed­ing the SMI using bunches with short rise times**. We also show an­a­lyt­i­cally and nu­mer­i­cally that in the lin­ear regime and after sat­u­ra­tion of the SMI the HI can be sup­pressed by a plasma-BNS damp­ing ana­logue. Sev­eral di­ag­nos­tics that could be used in ex­per­i­ments to mea­sure the SMI de­vel­op­ment and these ef­fects are also ex­plored.
*G. Xia et al., J. Plasma Phys., 1-7 (2012).
**J. Vieira et al., Phys. Plasmas 19, 063105 (2012). 		 
 
TUPEA008 Physics of the AWAKE Project 1179
 
  • P. Muggli, E. Oz, R. Tarkeshian
    MPI, Muenchen, Germany
  • C. Bracco, E. Gschwendtner, A. Pardons
    CERN, Geneva, Switzerland
  • A. Caldwell, O. Reimann
    MPI-P, München, Germany
  • K.V. Lotov
    BINP SB RAS, Novosibirsk, Russia
  • A.M. Pukhov
    HHUD, Dusseldorf, Germany
  • J. Vieira
    IPFN, Lisbon, Portugal
  • M. Wing
    UCL, London, United Kingdom
  
  The goal of the AWKAKE col­lab­o­ra­tion is the study of plasma wake­fields dri­ven by pro­ton (p+) bunches through ex­per­i­ments, sim­u­la­tions and the­ory. Pro­ton bunches are in­ter­est­ing wake­field dri­vers be­cause they can be ul­tra-rel­a­tivis­tic (TeVs/p+) and carry large amounts of en­ergy (>kJ). It was demon­strated in sim­u­la­tions* that ac­cel­er­a­tion of an elec­tron (e-) bunch from 10GeV to >500GeV can be achieved in ~500m of plasma dri­ven by a 1TeV, 100mi­cron-long, bunch with 1011 p+. Such short p+ bunches do not exist today. It was sug­gested** that a p+ bunch long com­pared to the plasma pe­riod can trans­versely self-mod­u­late and res­o­nantly drive wake­fields to large am­pli­tudes (~GV/m). Ini­tial ex­per­i­ments based on self-mod­u­la­tion in­sta­bil­ity (SMI) will use sin­gle 12cm-long CERN SPS bunches with 1-3·1011, 450GeV p+ to study physics of SMI. With a plasma den­sity of 7·1014/cc the plasma wave and mod­u­la­tion pe­riod is 1.3mm. The SMI sat­u­rates after ~3m with am­pli­tude in the GV/m range. Later a low en­ergy (~10MeV) wit­ness e- bunch will be in­jected at the SMI sat­u­ra­tion point. En­ergy gain over ~7m of plasma can reach the GeV level. Trans­la­tion from physics to ex­per­i­men­tal plan and setup will be pre­sented.
* A. Caldwell et al., Nature Physics 5, 363 (2009)
** N. Kumar et al., Phys. Rev. Lett. 104, 255003 (2010)