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The plasma afterburner has been proposed as a possible advanced acceleration scheme for a future linear collider. In this concept, a high energy electron(or positron) drive beam from an existing linac such as the SLC will propagate in a plasma section of density about one order of magnitude lower than the peak beam density. The particle beam generates a strong plasma wave wakefield which has a phase velocity equal to the velocity of the beam and this wakefield can be used to accelerate part of the drive beam or a trailing beam. Several issues such as the efficient transfer of energy and the stable propagation of the particle beam in the plasma are critical to the afterburner concept. We investigate the nonlinear beam-plasma interactions in such scenario using a new 3D particle-in-cell code called QuickPIC. Preliminary simulation results for electron acceleration, beam-loading and hosing instability will be presented. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

An expression for the maximum accelerating field in the narrow bunch limit (kpσr<<1) for a bi-Gaussian drive beam is derived from linear plasma wakefield theory. The optimal plasma density for a given beam (N, σz, σr) is found to be kpσz = [square_root_of_2] in the narrow beam limit. We also show that the previously obtained scaling law in which the wake amplitude increases with the inverse square of the bunch length must be modified by a weak logarithmic function of the beam spot size σr. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In current plasma-based accelerator experiments, very short bunches (100–150μm for E164 and 10–20 μm for E164X experiment at Stanford Linear Accelerator Center (SLAC)) are used to drive plasma wakes and achieve high accelerating gradients, on the order of 10–100GV/m. The self-fields of such intense bunches can tunnel ionize neutral gases and create the plasma. This may completely change the physics of plasma wakes. A 3-D object-oriented fully parallel PIC code OSIRIS is used to simulate various gas types, beam parameters, etc. to support the design of the experiments. The simulation results for real experiment parameters are presented. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]