Comparison of simulation codes for the beam dynamics of low-energy ions

Abstract

Results are presented of the simulation of low-energy ion dynamics with three different codes: KOBRA, IGUN and CPO. To share work between different codes one needs to be confident that they agree. For test cases, good agreement was found between the codes and analytical solutions. Where possible, results have been compared to experimental data from the CERN Laser Ion Source. These simulations are in general agreement with the data of the real beam line.c The following article has been submitted to Review of Scientific Instruments. After it is published, it will be found at http://ojps.aip.org/rsio/.Presented at ICIS2001, Oakland, California, USA 3-7 September 2001 Geneva, Switzerland October 2001 IntroductionSimulation of the extraction and low-energy transport of ions is a complex problem. In the case of the CERN Laser Ions Source (LIS) the beam is space-charge dominated and consists of a variety of charge states. To simulate the transport of beams through electrostatic fields, one starts from a set of measured beam parameters at the entry of the beam line. The result of the tracking depends then on the precision of the measurement, the field solver and the integration routine for the equation of motion of the particles.The simulation of particle transport in the space-charge domain can be shared between different codes if they have been cross-checked against each other. At CERN, the three codes KOBRA, IGUN and CPO are available. We have cross-checked these codes against each other with simple examples and have compared the results with experimental data available from the CERN LIS. The input beam distribution was identical for all codes. The codes were compared using two tests:1. Expansion of a space-charge dominated beam in a drift region without external fields; 2. Transport of particles in the electrostatic field of a Gridded Electrostatic Lens (GEL) [1] as used on the CERN LIS (see later description).

Ion thrusters for electric propulsion: Scientific issues developing a niche technology into a game changer

“…[138][139][140] A comparison between IGUN and KOBRA was published by Hanke and co-workers. 141 Tartz and co-workers have combined the IGUN code with a charge-exchange model to simulate the grid erosion for determining the thruster's lifetime. 142 The code was validated for various gridded ion thrusters.…”

Simulation of ion beam extraction and focusing system

“…The extraction of ions from plasma sources can be investigated by computer simulation. Two dimensional (2D) and three dimensional (3D) computer programs are now available for the optimization of ion extraction systems [2]. SIMION 3D 7.0 is a full windows program [3], featuring 3D electrostatic/magnetic arrays, data recording, charge repulsion, solid geometry definition files and a user program interface.…”

Achieving the Highest Accuracy With the BEM

“…It was shown some years ago [7,8] that for non-space-charge electrostatic 3D problems the CPO programs are typically one or two orders of magnitude more accurate than two representative FDM and FEM programs for the same computing time (or typically one or two orders of magnitude faster for the same accuracy), although this comparison has not been carried out for the more recent versions of all these methods. A comparison has also been carried out [9] for the space-charge simulation of a CERN laser ion source. A disadvantage is that the BEM tends to integrate trajectories more slowly, but a technique for alleviating this is discussed below.…”