Fusion Engineering and Design 80 (2006) 139–160 ARIES-AT magnet systems F. Dahlgren b,∗ , T. Brown b , P. Heitzenroeder b , L. Bromberg a , and The ARIES Team a M.I.T., Plasma Science & Fusion Center, NW16-108, Cambridge, MA 02139-4307, USA b Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543-0451, USA Available online 21 October 2005 Abstract This report presents a conceptual design of the magnet systems for an advanced tokamak fusion reactor (ARIES-AT). The main focus of the paper is to anticipate and extrapolate the current state-of-the-art in high temperature superconductors and coil design, and apply them to an advanced commercial fusion reactor concept. The current design point is described and supported with a preliminary structural analysis and a discussion of the merits, performance, and economics of high temperature vs. low temperature superconductors in an advanced fusion reactor design. © 2005 Elsevier B.V. All rights reserved. Keywords: Fusion; Magnet; Superconductivity; ARIES; HTS; YBCO 1. Introduction The ARIES-AT reactor is a conceptual commer- cial reactor based on aggressive extrapolation from the present engineering database, with modest extrapola- tion in the physics database. In contrast with ARIES-RS [1], both the physics and the engineering are more aggressive. The design of the toroidal field magnet is slightly less demanding than ARIES-RS due to improved physics. As with the ARIES-RS magnet [2], the magnet is steady state, with a limited number of transients. The magnet issues for ARIES-AT are different from previ- ∗ Tel.: +1 609 243 2173. E-mail address: fdahlgre@pppl.gov (F. Dahlgren). ous ARIES designs, in that they are manufactured using high temperature superconductors (HTS). HTS have been shown to have high current densities at high fields, and therefore, magnets can be designed for high field operation, limited by structural issues. In the system code analysis, the use of a high magnetic field option was allowed. However, it was found that the system optimized (in terms of cost of electricity) at moderate magnetic fields that are achievable with con- ventional low temperature superconductors. The peak field in ARIES-AT is 11.1T at the TF coil and 9T at the PF coils. The use of high-T c (T c —critical temperature) has important implications on the critical issues of the toroidal and the poloidal field systems [3]. The objec- tive of the magnet work in ARIES-AT is to review 0920-3796/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.fusengdes.2005.06.357