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Decyk, V.K.

Paper Title Page
TPAE046 Modeling Self-Ionized Plasma Wakefield Acceleration for Afterburner Parameters Using QuickPIC 2905
 
  • M. Zhou, C.E. Clayton, V.K. Decyk, C. Huang, D.K. Johnson, C. Joshi, W. Lu, W.B. Mori, F.S. Tsung
    UCLA, Los Angeles, California
  • F.-J. Decker, R.H. Iverson, C.L. O'Connell, D.R. Walz
    SLAC, Menlo Park, California
  • S. Deng, T.C. Katsouleas, P. Muggli, E. Oz
    USC, Los Angeles, California
 
  Funding: DOE

A plasma wakefield accelerator (PWFA) has been proposed as a way to double the energy of a future linear collider. This afterburner concept will require meter long uniform plasmas. For the parameters envisaged in possible afterburner stages, the self-fields of the particle beam are intense enough to tunnel ionize some neutral gases such as lithium. Tunnel ionization has been investigated as a way for the beam itself to create the plasma.* Furthermore, tunnel ionization in a neutral or partially pre-ionized gas may create new plasma electrons and alter the plasma wake.*,** Unfortunately, it is not possible to model a PWFA with afterburner parameters using the models described in Bruhwiler et al. and Deng et al. Here we describe the addition of a tunnel ionization package using the ADK model into QuickPIC, a highly efficient quasi-static particle in cell (PIC) code which can model a PWFA with afterburner parameters. There is excellent agreement between QuickPIC and OSIRIS(a full PIC code) for pre-ionized plasmas. Effects of self-ionization on hosing instability –one of the most critical issues to overcome to make an afterburner a reality – for a bunch propagating in a plasma hundreds of betatron oscillations long will be discussed.

*D. L. Bruhwiler et al., Phys. Plasmas 10 (2003), p. 2022. **S. Deng et al., Phys. Rev. E, 68, 047401 (2003).

 
ROPB007 3-D Parallel Simulation Model of Continuous Beam-Electron Cloud Interactions 549
 
  • A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • E. Benedetto, F. Zimmermann
    CERN, Geneva
  • V.K. Decyk, C. Huang, W.B. Mori
    UCLA, Los Angeles, California
  • G. Rumolo
    GSI, Darmstadt
 
  A 3D Particle-In-Cell model for continuous modeling of beam and electron cloud interaction in a circular accelerator is presented. A simple model for lattice structure, mainly the Quadruple and dipole magnets and chromaticity have been added to a plasma PIC code, QuickPIC, used extensively to model plasma wakefield acceleration concept. The code utilizes parallel processing techniques with domain decomposition in both longitudinal and transverse domains to overcome the massive computational costs of continuously modeling the beam-cloud interaction. Through parallel modeling, we have been able to simulate long-term beam propagation in the presence of electron cloud in many existing and future circular machines around the world. The exact dipole lattice structure has been added to the code and the simulation results for CERN-SPS and LHC with the new lattice structure have been studied. Also the simulation results are compared to the results from the two macro-particle modeling for strong head-tail instability. It is shown that the simple two macro-particle model can capture some of the physics involved in the beam- electron cloud interaction qualitatively.  
FPAP022 Long Time Simulation of LHC Beam Propagation in Electron Clouds 1769
 
  • B. Feng, A.F. Ghalam, T.C. Katsouleas
    USC, Los Angeles, California
  • E. Benedetto, F. Zimmermann
    CERN, Geneva
  • V.K. Decyk, W.B. Mori
    UCLA, Los Angeles, California
 
  In this report we show the simulation results of single-bunch instabilities caused by interaction of a proton beam with an electron cloud for the Large Hadron Collider (LHC) using the code QuickPIC [1]. We describe three new results: 1) We test the effect of the space charge of the beam on itself; 2) we add the effect of dispersion in the equation of motion in the x direction, and 3) we extend previous modeling by an order of magnitude (from 50ms to 500ms) of beam circulation time. The effect of including space charge is to change the emittance growth by less than a few percent. Including dispersion changes the plane of instability but keeps the total emittance approximately the same. The longer runs indicate that the long term growth of electron cloud instability of the LHC beam cannot be obtained by extrapolating the results of short runs.