Paper  Title  Page 

TUEPPB006  Direct Numerical Modeling of ECloud Driven Instability of Three Consecutive Batches in the CERN SPS  1125 


Funding: Supported by the USDOE under Contract DEAC0205CH11231, the SciDAC program ComPASS and the USLHC Accelerator Research Program (LARP). Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. The simulation package WARPPOSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct selfconsistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARPPOSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the ecloud driven transverse instability, leading to a net increase in predicted electron density. Used resources of NERSC. 

WEEPPB003  Modeling of 10 GeV1 TeV LaserPlasma Accelerators Using Lorentz Boosted Simulations  2172 


Funding: Supported by USDOE Contracts DEAC0205CH11231 and DEAC5207NA27344, USLHC program LARP, and USDOE SciDAC program ComPASS. Modeling of laserplasma wakefield accelerators in an optimal frame of reference [J.L. Vay, Phys. Rev. Lett. 98 130405 (2007)] allows direct and efficient fullscale modeling of deeply depleted and beam loaded laserplasma stages of 10 GeV1 TeV (parameters not computationally accessible otherwise). This verifies the scaling of plasma accelerators to very high energies and accurately models the laser evolution and the accelerated electron beam transverse dynamics and energy spread. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively. Agreement at the percentage level is demonstrated between simulations using different frames of reference for a 0.1 GeV class stage. Obtaining these speedups and levels of accuracy was permitted by solutions for handling data input (in particular particle and laser beams injection) and output in a relativistically boosted frame of reference, as well as mitigation of a highfrequency instability that otherwise limits effectiveness. Used resources of NERSC, supported by USDOE Contract DEAC0205CH11231. 

WEPPP076  Analysis of Numerical Noise in ParticleInCell Simulations of SingleBunch Transverse Instabilities and Feedback in the CERN SPS  2888 


Funding: Work supported by the USDOE and the USLHC Accelerator Research Program LARP under Contract DEAC0205CH11231. Used resources of NERSC and the Lawrencium cluster at LBNL The operation at high current of the SPS at CERN is limited by transverse SingleBunch instabilities generated by the effect of electron clouds. A model of a high bandwidth feedback control system has been implemented in the macroparticle code WARP to study bunch dynamics and identify system requirements for the efficient damping of singlebunch transverse instability. We analyze the effect of numerical noise and choice of simulation parameters on the modeling of beam dynamics, focusing in particular on the investigation of the feedback system requirements of minimum power to damp the instability and frequency bandwidth given a fixed gain. We report on simulation results and discuss the plans for the future improvements of the feedback model. 

THPPP096  Recent Developments and Applications of the Beam Simulation Code Warp  3957 


Funding: Supported by USDOE Contracts DEAC0205CH11231 and DEAC5207NA27344. Used resources of NERSC, supported by USDOE Contract DEAC0205CH11231. The ParticleInCell Framework Warp is being developed by the Heavy Ion Fusion US program to guide the development of accelerators for high energy density experiments and ultimately for inertial fusion energy. Accurate predictions of the beam phase space are important for understanding the limits to the pulse compression, in particular for NDCXII now under construction at LBNL. We will present a new numerical method that correct for the effects of linear correlations, offering accurate mapping of energy spread and temperature. The interaction of the beam with the neutralizing plasma can affect non linearly the phase space of the beam. We will present fully kinetic simulation of the beam/plasma interaction aimed toward a better understanding of these effects and possibilities for mitigating or exploiting them. We will also present an application of the original warped coordinate algorithm to the modeling of charge separation in the transition of a 50 MeV singly charged Uranium beam to higher charge state upon passing through a stripping foil, with the goal of decreasing the cost of a Heavy Ion Fusion driver. We also describe studies of beams in plasmas and of injector optimization. Used resources of NERSC. 
