BNL, Upton, Long Island, New York
The future electron-ion collider eRHIC - under design at BNL - will collide the electron beam accelerated in an energy recovery linacs with protons or ions circulating in the accelerator ring. This linac-ring collisions bring up a number of unique features in beam-beam interactions. For in-depth studies of the beam-beam effects and resulting the luminosity limitations, we developed a dedicated simulation code. We researched the effects of the mismatch, the disruption and the pinching on the electron beam. Relevant dynamics of the proton beam including the kink instability in combination with incoherent beam-beam effects was also explored in detail. In this talk we will describe the main features of our simulation code and will present the most important simulations results.
BNL, Upton, Long Island, New York
In this article we will review the computational challenges in the beam-beam simulation for the polarized proton run of the Relativistic Heavy Ion Collider (RHIC). The difficulties in our multi-particle and million turn tracking to simulate the proton beam lifetime and proton beam emittance growth due to head-on beam-beam interaction and head-on beam-beam compensation are presented and discussed. Soultions to obtain meaning physics results from these trackings are proposed and tested. In the end we will report the progress in the benchmarking of the RHIC operational proton beam lifetime.
LBNL, Berkeley, California
CERN, Geneva
SLAC, Menlo Park, California
A new proton synchrotron, the PS2, was proposed to replace the current proton synchrotron at CERN for the LHC injector upgrade. Nonlinear space charge effects could cause significant beam emittance growth and particle losses and limit the performance of the PS2. In this paper, we report on simulation studies of the potential space-charge effects at the PS2 using three-dimensional self-consistent macro-particle tracking. We will discuss the impact of space-charge effects on the beam emittance growth, especially due to synchro-betatron coupling, aperture sizes, initial painted distribution, and RF ramping schemes. The computational model used in the simulation will also be discussed.
Fermilab, Batavia
IIT, Chicago, Illinois
Illinois Institute of Technology, Chicago, Illinois
The Fermilab Booster beam is exposed to magnet laminations, resulting in impedance effects much larger than resistive wall effects in a beam pipe. We present a calculation of wake functions in laminated magnets, which show large values at distances of the order of a few meters, but decrease quickly to zero beyond that. Therefore, strong in-bunch and nearest-bunch effects are present. We show realistic Synergia simulations of the Booster using these wake functions and space-charge solvers appropriate for the various geometries of the constituent elements of the machine. The simulation of tune shifts is in good agreement with experimental data. We find that wake fields in the Booster magnet laminations strongly increase beam emittance and have the potential to cause significant beam loss.
Northern Illinois University, DeKalb, Illinois
Currently when the effects of space charge on a beam line are calculated the problem is solved using a particle in cell method of advancing a large number of macroparticles. If quantities such as space charge induced tune shifts are desired it is difficult to determine which of the many variables that make up the beam is the cause. The new method presented here adds the effects of space charge to a nonlinear transfer map, this allows us to use normal form methods to directly measure quantities like the tune. This was done using the code COSY Infinity which makes use of differential algebras, which allow the direct calculation of how the tune depends on the beam current. The method involves finding the high order statistical moments of the particles, determining the distribution function, and finally the potential. In order to advance the particles as accurately as possible a fast multipole method algorithm is used. In this talk we present the new methods and how they allow us to follow the time evolution of an intense beam and extract its nonlinear dynamics. We will also discuss how these methods can improve the design and operation of current and future high intensity facilities.