Spheromak Gun for Inductive flux Injection (PPPL No. M-1035)

Web Published:

Spheromak Gun for Inductive flux Injection

Princeton Docket # 22-3902

PPPL and a collaborator have proposed the formation of a high flux spheromak by an inductive flux injection coaxial gun. The basic approach of the scheme is based on a principle in which plasmas relax toward the minimum energy state during spheromak formation, independent of initial conditions. Inductive formation of a spheromak was demonstrated 40 years ago by Yamada et al, PRL 1981 by utilizing a relaxation process towards the Taylor minimum energy state using flux-core-based spheromak formation. Proposed is a formation scheme of a high flux spheromak by using an inductive co-axial gun. 


  • Deployed on field-reversed configuration (FRC) fusion for creation of initial target plasma


  • Higher flux and denser FRC formation 
  • Reduced impurity injection due to electrode discharges


Masaaki Yamada is Distinguished Research Fellow at Princeton Plasma Physics laboratory of Princeton University. Dr. Yamada received his B.S. degree in Applied Physics and M.S. degree in Nuclear Engineering in 1966 and 1968, respectively, both from the University of Tokyo, and received his Ph.D. in Physics from the University of Illinois in 1973. He was engaged in many basic plasma physics research programs that were relevant to both fusion and space-astrophysics.During 1978-1988, he headed the research effort on the spheromak, at that time a new concept for fusion, utilizing the S-1 device. Since the early 1990′s, he has pioneered a new experiment, which became the MRX at PPPL, to explore the fundamental physics of magnetic reconnection. The MRX research has made key discoveries on magnetic reconnection together with many important findings on plasma astrophysics.

Intellectual Property Status

Princeton is currently seeking commercial partners for the further development and commercialization of this opportunity. 


Chris Wright

Princeton University Office of Technology Licensing • (609) 258-6762• cw20@princeton.edu

Laurie Bagley

Princeton Plasma Physics Laboratory • (609) 243-2425• lbagley@pppl.gov


Patent Information:
For Information, Contact:
Chris Wright
Licensing Associate
Princeton University
Masaaki Yamada
Hiroshi Gota