Radial Confinement in Non-Symmetric Quadrupolar Mirrors

• Published in: Journal of fusion energy 2013-06, Vol.32 (3), p.327-335
• Main Authors: Hagnestål, A., Ågren, O., Moiseenko, V. E.
• Format: Article
• Language: English
• Subjects: Anchors; Approximation; Charged particles; Coiling; Confinement; Devices; Electric fields; Energy Systems; Engineering Science with specialization in Science of Electricity; Fysik med inriktning mot rymd- och plasmafysik; Invariants; Magnetic fields; Mirrors; Nuclear Energy; Nuclear Fusion; Original Research; Physics; Physics and Astronomy; Physics with specialization in Space and Plasma Physics; Plasma Physics; Quadrupolar mirror machine; radial transport; Sustainable Development; Symmetry; Tandem mirrors; Teknisk fysik med inriktning mot elektricitetslära; Tokamaks; Trapped particles
• ISSN: 0164-0313; 1572-9591; 1572-9591
• DOI: 10.1007/s10894-012-9573-x

Charged particles in symmetric quadrupolar mirrors are radially confined and have an associated radial invariant. In a symmetric quadrupolar field the magnetic field modulus satisfies along the axis if z  = 0 defines the field minimum of the mirror, and the quadrupolar field has a corresponding symmetry. The field in the anchor cells of a tandem mirror need not obey a corresponding symmetry. In this paper, the radial confinement of non-symmetric mirrors is examined by tracing sample ions in the magnetic field. It is found that for non-symmetric mirrors, particles are typically not confined, and no radial invariant exists for such devices. Without attention to this effect in the field and coil design, radial confinement of trapped particles may be lost.