Plasma and Fusion Research

Volume 15, 2402069 (2020)

Regular Articles

Behavior of a Tracer-Containing Compact Toroid in a Transverse Magnetic Field
Taichi SEKI, Daichi KOBAYASHI, Rika SASAKI, Asuna MINAMIGI, Tomohiko ASAI, Hiroshi GOTA1), Thomas ROCHE1), Tadafumi MATSUMOTO1,2), Toshiki TAKAHASHI3), Naoki TAMURA4) and Yoshiro NARUSHIMA4)
College of Science and Technology, Nihon University, Tokyo 101-8308, Japan
TAE Technologies, Inc., Foothill Ranch, CA 92610, USA
University of California at Irvine, Irvine, CA 92697, USA
Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan
National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
(Received 29 November 2019 / Accepted 19 July 2020 / Published 1 September 2020)


Studying impurity behavior in a magnetically confined plasma is essential for fusion reactor developments. A tracer-containing compact toroid (TCCT) injection have been developed as a new tracer injection technique for studying impurity accumulation and behavior in magnetically confined fusion plasmas. We generated and ejected the TCCT using a compact toroid (CT) injector that had successfully demonstrated CT injection fueling into a large field-reversed configuration (FRC). Tracer ions, e.g., tungsten, copper, and aluminum, are supplied by an independently controlled tracer source attached to the CT injector. The plasma containing tracer ions is accelerated and ejected by Lorentz self-force as the TCCT. To investigate whether tracer ions can be injected into the plasma without separation from the TCCT, we experiment by injecting the TCCT injection into a transverse magnetic field, emulating a confinement magnetic field of the FRC plasma.


tracer-containing compact toroid, compact toroid injection, magnetized coaxial plasma gun, impurity transport, tracer, field-reversed configuration

DOI: 10.1585/pfr.15.2402069


  • [1] G.R. McKee et al., Phys. Plasmas 7, 1870 (2000).
  • [2] B. Zurro et al., Plasma Phys. Control. Fusion 56, 124007 (2014).
  • [3] N. Tamura et al., J. Phys. Conf. Ser. 823, 012003 (2017).
  • [4] D. Kobayashi, T. Asai, S. Yamada et al., Rev. Sci. Instrum. 89, 10I111 (2018).
  • [5] T. Asai, T. Matsumoto, T. Roche et al., Nucl. Fusion 57, 076018 (2017).
  • [6] T. Matsumoto et al., Rev. Sci. Instrum. 87, 053512 (2016).
  • [7] T. Asai, H. Itagaki, H. Numasawa et al., Rev. Sci. Instrum. 81, 10E119 (2010).