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Title: A 2D Particle in Cell model for ion extraction and focusing in electrostatic accelerators

Negative ions are fundamental to produce intense and high energy neutral beams used to heat the plasma in fusion devices. The processes regulating the ion extraction involve the formation of a sheath on a scale comparable to the Debye length of the plasma. On the other hand, the ion acceleration as a beam is obtained on distances greater than λ{sub D}. The paper presents a model for both the phases of ion extraction and acceleration of the ions and its implementation in a numerical code. The space charge of particles is deposited following usual Particle in Cell codes technique, while the field is solved with finite element methods. Some hypotheses on the beam plasma transition are described, allowing to model both regions at the same time. The code was tested with the geometry of the NIO1 negative ions source, and the results are compared with existing ray tracing codes and discussed.
Authors:
;  [1] ;  [2]
  1. Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy)
  2. INFN-LNL, Viale dell’ Università 2, 35020 Legnaro (PD) (Italy)
Publication Date:
OSTI Identifier:
22254100
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 2; Conference: ICIS 2011: 14. international conference on ion sources, Giardini-Naxos, Sicily (Italy), 12-16 Sep 2011; Other Information: (c) 2013 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 43 PARTICLE ACCELERATORS; ANIONS; DEBYE LENGTH; ELECTROSTATIC ACCELERATORS; EXTRACTION; FINITE ELEMENT METHOD; ION BEAMS; PARTICLES; PLASMA; SPACE CHARGE; THERMONUCLEAR DEVICES