MOOCS —  Beam Dynamics II   (28-Mar-11   13:30—15:30)
Chair: V.V. Danilov, ORNL, Oak Ridge, Tennessee, USA
Paper Title Page
MOOCS1 Non-neutral Plasma Traps for Accelerator-free Experiments on Space-charge-dominated Beam Dynamics 46
 
  • H. Okamoto, K. Ito
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Higaki
    Hiroshima University, Higashi-Hiroshima, Japan
 
  The beam physics group of Hiroshima University has developed compact plasma trap systems to explore diverse fundamental aspects of space-charge-dominated beam dynamics. At present, two Paul ion traps are in operation, one more under construction, and a Penning-Malmberg type trap is also working. These very compact, accelerator-free experiments are based on the isomorphism between non-neutral plasmas in a trap and charged-particle beams traveling in a periodic focusing channel. Systematic studies of coherent betatron resonances, ultralow-emittance beam stability, and halo formation are in progress employing both types of traps. Latest experimental results and possible future plans are addressed in this paper.  
slides icon Slides MOOCS1 [9.193 MB]  
 
MOOCS2 Numerical Verification of the Power Transfer and Wakefield Coupling in the CLIC Two-beam Accelerator 51
 
  • A.E. Candel, K. Ko, Z. Li, C.-K. Ng, V. Rawat, G.L. Schussman
    SLAC, Menlo Park, California, USA
  • A. Grudiev, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
 
  The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator concept envisions large complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC's parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.  
slides icon Slides MOOCS2 [286.042 MB]  
 
MOOCS3 Numerical and Analytical Studies of Matched Kinetic Quasi-Equilibrium Solutions for an Intense Charged Particle Beam Propagating Through a Periodic Focusing Quadrupole Lattice 56
 
  • E. Startsev, R.C. Davidson, M. Dorf
    PPPL, Princeton, New Jersey, USA
 
  Funding: Research supported by the U. S. Department of Energy.
A recently developed novel perturbative Hamiltonian transformation method which allows the determination of approximate matched kinetic quasi-equilibrium solutions for an intense charged particle beam propagating through a periodic focusing quadrupole lattice is presented.* Using this method we have identified numerically the class of self-consistent periodic kinetic 'equilibria' for intense beam propagation in alternating-gradient focusing systems, and extended the nonlinear perturbative particle simulation method to intense beam propagation in such systems. The new method has been implemented in the nonlinear perturbative particle-in-cell code BEST which is used to study properties of the newly constructed beam 'equilibria'. The results of these studies are presented and analyzed in detail.
* E.A. Startsev, R.C. Davidson and M. Dorf, Phys. Rev. ST Accel. Beams 13, 064402 (2010).
 
slides icon Slides MOOCS3 [0.508 MB]  
 
MOOCS4 Time-Dependent Phase-Space Measurements of the Longitudinally Compressing Beam in NDCX-I 61
 
  • S.M. Lidia, G. Bazouin, P.A. Seidl
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore Warm Dense Matter physics. A ~150 kV, ~500 ns ramped voltage pulse is applied to a ~300 keV, 5-10 μs, 25 mA K+ ion beam across a single induction gap. The velocity modulated beam compresses longitudinally during ballistic transport along a space-charge-neutralizing plasma transport line, resulting in ~3A peak current with ~2-3 ns pulse durations (FWHM) at the target plane. Transverse final focusing is accomplished with a ~8 T, 10 cm long pulsed solenoid magnet. Time-dependent focusing in the induction gap, and chromatic aberrations in the final focus optics limit the peak fluence at the target plane for the compressed beam pulse. We report on time-dependent phase space measurements of the compressed pulse in the ballistic transport beamline, and measurement of the time-dependent radial impulses derived from the interaction of the beam and the induction gap voltage. We present results of start-to-end simulations to benchmark the experiments. Fast correction strategies are discussed with application to both NDCX-I and to the new NDCX-II accelerator.
 
slides icon Slides MOOCS4 [7.432 MB]  
 
MOOCS5 Space-charge Effects in H Low-energy Beam Transport of LANSCE 64
 
  • Y.K. Batygin, C. Pillai, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
 
  The 750-keV low-energy beam transport of the Los Alamos Neutron Science Center (LANSCE) linac consists of two independent beam lines for simultaneous injection of H+ and H beams into the linear accelerator. While transport of the H+ beam is seriously affected by uncompensated space charge forces, the same effect for H is hidden by presence of multiple beam collimators and beam chopping. Recent results from beam development experiments indicate a significant influence of space charge on H beam dynamics in the low-energy beam transport. Measurements of beam emittance along beam transport show the formation of S-shaped filamentation in the particle distribution phase space, typical with the presence of non-linear space charge forces. Results are supported by particle tracking simulations with the PARMILA, BEAMPATH, and TRACE codes.  
slides icon Slides MOOCS5 [6.304 MB]