Moments in particle-in-cell simulations

Conference · Tue Oct 01 04:00:00 EDT 1985 · IEEE Trans. Nucl. Sci.; (United States)

OSTI ID:6017349

Berz, M M; Lysenko, W P

The moment equations that form the basis of the BEDLAM simulation code can also be used as a check on Particle-In-Cell (PIC) simulations. Moments can be computed as sums over the macroparticles used in the PIC simulations. These moments should satisfy the moment equations if the simulation is valid. A check has been done to sixth order for two cases: the RFQRZP code, which simulated a radio-frequency quadrupole (RFQ) linac, and the BEAMTRACE code, which simulated the final focusing system in a heavy ion fusion facility. We observed how well the moment equations were satisfied for various values of the independentvariable step size and the number of macroparticles. Generally, we found that the PIC codes satisfied the moment equations very well. Because our modified PIC codes were able to compute moments that satisfied the correct moment equations, we were able to use our modified version of RFQRZP, which we called RFQMOM, to work on another problem. Every moment simulation code has to include some truncation approximation. The error of this approximation can be determined by RFQMOM before actually writing the moment code. As an example, we investigated the accuracy of the truncation approximation that is used in the BEDLAM code.

• Research Organization: Los Alamos National Laboratory, Los Alamos, NM
• OSTI ID: 6017349
• Report Number(s): CONF-850504-
• Conference Information: Journal Name: IEEE Trans. Nucl. Sci.; (United States) Journal Volume: NS-32:5
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ACCELERATORS
B CODES
BEAM DYNAMICS
COMPUTER CODES
COMPUTERIZED SIMULATION
ELECTRIC MOMENTS
LINEAR ACCELERATORS
MAGNETIC MOMENTS
QUADRUPOLE LINACS
R CODES
RF SYSTEMS
SIMULATION