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Title: A novel adaptive time stepping variant of the Boris–Buneman integrator for the simulation of particle accelerators with space charge

We show that adaptive time stepping in particle accelerator simulation is an enhancement for certain problems. The new algorithm has been implemented in the OPAL (Object Oriented Parallel Accelerator Library) framework. The idea is to adjust the frequency of costly self-field calculations, which are needed to model Coulomb interaction (space charge) effects. In analogy to a Kepler orbit simulation that requires a higher time step resolution at the close encounter, we propose to choose the time step based on the magnitude of the space charge forces. Inspired by geometric integration techniques, our algorithm chooses the time step proportional to a function of the current phase space state instead of calculating a local error estimate like a conventional adaptive procedure. Building on recent work, a more profound argument is given on how exactly the time step should be chosen. An intermediate algorithm, initially built to allow a clearer analysis by introducing separate time steps for external field and self-field integration, turned out to be useful by its own, for a large class of problems.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [4] ;  [5]
  1. ETH Zürich, Computer Science Department, Universitätsstrasse 6, 8092 Zürich (Switzerland)
  2. (Switzerland)
  3. (United States)
  4. Paul Scherrer Institute, CH-5234 Villigen (Switzerland)
  5. (China)
Publication Date:
OSTI Identifier:
22382105
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Computational Physics; Journal Volume: 273; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCELERATORS; ALGORITHMS; COMPUTERIZED SIMULATION; ORBITS; PHASE SPACE; RESOLUTION; SPACE CHARGE