ALCBEAM - Neutral beam formation and propagation code for beam-based plasma diagnostics

作者：Bespamyatnov I O^*; Rowan W L; Liao K T

来源：Computer Physics Communications, 2012, 183(3): 669-676.

DOI：10.1016/j.cpc.2011.10.019

• Neutral beam
• NBI
• DNB
• Injection
• Simulation
• Beam-gas attenuation
• Beam-plasma attenuation
• Alcator C-Mod tokamak

ALCBEAM is a new three-dimensional neutral beam formation and propagation code. It was developed to support the beam-based diagnostics installed on the Alcator C-Mod tokamak. The purpose of the code is to provide reliable estimates of the local beam equilibrium parameters: such as beam energy fractions, density profiles and excitation populations. The code effectively unifies the ion beam formation, extraction and neutralization processes with beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures. This paper describes the physical processes interpreted and utilized by the code, along with exploited computational methods. The description is concluded by an example simulation of beam penetration into plasma of Alcator C-Mod. The code is successfully being used in Alcator C-Mod tokamak and expected to be valuable in the support of beam-based diagnostics in most other tokamak environments.
Program summary
Program title: ALCBEAM
Catalogue identifier: AEKU_v1_0
Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEKU_v1_0.html
Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland
Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html
No. of lines in distributed program, including test data, etc.: 66 459
No. of bytes in distributed program, including test data, etc.: 7 841 051
Distribution format: tar.gz
Programming language: IDL
Computer: Workstation, PC
Operating system: Linux
RAM: 1 GB
Classification: 19.2
Nature of problem: Neutral beams are commonly used to heat and/or diagnose high-temperature magnetically-confined laboratory plasmas. An accurate neutral beam characterization is required for beam-based measurements of plasma properties. Beam parameters such as density distribution, energy composition, and atomic excited populations of the beam atoms need to be known.
Solution method: A neutral beam is initially formed as an ion beam which is extracted from the ion source by high voltage applied to the extraction and accelerating grids. The current distribution of a single beamlet emitted from a single pore of IOS depends on the shape of the plasma boundary in the emission region. Total beam extracted by IOS is calculated at every point of 3D mesh as sum of all contributions from each grid pore. The code effectively unifies the ion beam formation, extraction and neutralization processes with neutral beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures.
Running time: 10 min for a standard run. Published by Elsevier B.V.

• 出版日期2012-3