Primary Intelligence Asset
Nihon University Compact Toroid Injection 2016
Declassified Public record OCR verified
INTEL
Executive Summary
Researchers have developed a method to 'refuel' a fusion energy experiment by shooting high-speed plasma rings, called Compact Toroids, into a containment vessel. This technique successfully replenishes lost particles, helping to maintain the stability and density of the plasma needed for potential fusion power.
Analysis Confidence: High
ST_CODE: 3AFEFA
System Metadata
Source ID
DOC-NIHON_UN
Process Date
8/9/2026
Integrity Hash
SHA256-7fuv6kiixq7...
Indexer Status
COMPLETE
Initializing_Secure_Viewer...
INVESTIGATIVE ANALYSIS
Summary
Researchers have developed a method to 'refuel' a fusion energy experiment by shooting high-speed plasma rings, called Compact Toroids, into a containment vessel. This technique successfully replenishes lost particles, helping to maintain the stability and density of the plasma needed for potential fusion power.
Origin
The document was authored by Tadafumi Matsumoto of Nihon University (Japan) as part of a collaboration with the University of California at Irvine and Tri Alpha Energy. It was presented at the US-Japan CT2016 workshop.
Purpose
The research aimed to address the high particle loss rate in the C-2U Field-Reversed Configuration (FRC) fusion device by developing a Compact Toroid (CT) injector capable of penetrating the magnetic field to provide refueling.
Why It Matters
" This document is highly relevant to the study of Field-Reversed Configuration (FRC) fusion, a key technology often investigated for both clean energy and advanced aerospace propulsion. It establishes a clear link between academic institutions (Nihon, UCI) and Tri Alpha Energy (now TAE Technologies), illustrating the transition of high-energy density physics from theoretical research to practical, large-scale experimental hardware. "
Key Claims
- › The CT injector achieved plasma velocities exceeding 100 km/s and densities of 1.5 to 3.5 × 10^15 cm^-3.
- › The C-2U device particle loss rate was measured between 2.0 and 4.0 × 10^18 particles per millisecond.
- › The research was conducted under a Memorandum of Understanding (MOU) between the University of California at Irvine (UCI) and Nihon University (NU).
- › The CT injector utilizes a gun current of up to 190 kA and a total CT energy of up to 0.7 kJ.
- › Tadafumi Matsumoto, T. Tajima, and H. Gota are listed as key researchers involved in the C-2U FRC project.
Contribution to the Field
This document provides specific engineering specifications for magnetized coaxial plasma guns, including the use of tungsten coating and specific installation angles (NW and SE) for multi-pulse injection on the C-2U device.
External Primary Sources (3)
Verified external sources that corroborate the claims in this document.
patent
US Patent 9,947,420 B2 — Magnetic field plasma confinement for compact fusion power
conference 2019
Recent Achievements in the C-2W Field-Reversed Configuration Experiment — APS DPP19
TAE Technologies
paper 2019-06-05
Formation of hot, stable, long-lived field-reversed configuration plasmas on the C-2W device — Nuclear Fusion
H. Gota et al.
Full Transcript
Transcript
Page 1 of 2
INTRODUCTION
Compact Toroid Injection into C-2U FRC US-Japan CT2016, August 24 Tadafumi Matsumoto Nihon University NIHON UNIVERSITY CT-Work Shop2016 2 Presenter: Tadafumi Matsumoto Collaborations Nihon University University of California at Irvine Tri Alpha Energy • This project has been conducted in part under the MOU on the research cooperation between UCI and NU. • Integral partnership • Development of a compact toroid injector for particle refueling CT-Work Shop2016 3 Presenter: Tadafumi Matsumoto H. Gota T. Roche T. Asai* E. Garate E. Granstedt I. Allfrey T. Valentine J. Kinley, C. Hooper M. Cordero P. Feng W. Waggoner M. Conroy M. Morehouse D. Sheftman T. Tajima* *Nihon University Acknowledgements *UCI CT-Work Shop2016 4 Presenter: Tadafumi Matsumoto • Motivation • CT Injector Overview • CT injection into C-2U FRC • Upgrade • Summary Outline CT-Work Shop2016 5 Presenter: Tadafumi Matsumoto Outline • Motivation • CT Injector Overview • CT injection into C-2U FRC • Upgrade • Summary CT-Work Shop2016 6 Presenter: Tadafumi Matsumoto Requirement for CT Injection • In C-2U particle loss rate was 2.0 – 4.0× 10 18 / ms • To penetrate the FRC, the kinetic energy density of the CT must be higher than 4 k J/m 3 , which is magnetic field energy inside the confinement vessel, e.g., density of CT 1×10 15 cm -3 , velocity 70 km/s • The CT Injector is a viable refueling candidate Motivation 012345 0.5 1.0 1.5 2.0 2.5 0 time (ms) Particle number (x10 19 ) Loss rate: 2.5x10 18 Time evolution of particle loss rate of the C-2U FRC CT-Work Shop2016 7 Presenter: Tadafumi Matsumoto Outline • Motivation • CT Injector Overview Ø Developed CT injector Ø Test Stand Ø CT Parameters • CT injection into C-2U FRC • Upgrade • Summary CT-Work Shop2016 8 Presenter: Tadafumi Matsumoto Tungsten coating • The surface of the inner electrode is coated with tungsten by Vacuum Plasma Spraying Extension electrode • The roles of the extension electrode are; protect ceramic break from the plasma, and suppress diffusion of the magnetic field. Gas port Magnetized Coaxial Plasma Gun Outer Electrode (I.D 83.1 mm) Bias Coil Inner Electrode (O.D. 54 mm) Extension Gas Puff Valve (1) Biasing magne7c field applied and working gas is injected between electrode. (2) Forma7on bank is triggered to begin breakdown. The plasma is accelerated by Lorentz force. (3) The accelerated plasma is captured by bias field. Then the reconnec7on occurs. (4) The magne7zed plasma is ejected. Working gas Bias field Breakdown Accelerate by J r ×B θ capture Reconnec7on Toroidal current CT-Work Shop2016 9 Presenter: Tadafumi Matsumoto CT Injector Dri M tube • Magne7c probe • Dispersion Inter. • PMT • Triple Langmuir probe Transverse Field Coil Expansion glass chamber • Magne7c probe • PMT • Triple Langmuir probe å Drift tube • The drift tube diagnostics measure typical CT parameters; velocity, density, and temperature. Glass chamber • The transverse magnetic field coil simulates C-2U’s magnetic field. Test Bed with Transverse magnetic field coil CT-Work Shop2016 10 Presenter: Tadafumi Matsumoto Transverse field region èCT Compressed Field-free region èCT Expands CT was compressed by magnetic field w/o Transverse field w/ Transverse field CT-Work Shop2016 11 Presenter: Tadafumi Matsumoto n Required parameters >70 km/s, 1.0×10 15 cm -3 n Gun current up to 190 k A n Total energy of CT up to 0.7 k J n Velocity >100 km/s n Density 1.5 - 3.5×10 15 cm -3 n Electron temperature 20 - 40 e V n Energy Density 50 k J/m 3 CT Performance n Developed CT injector achieved the requirement n CT will penetrate C-2U Field n Diameter of CT in the transverse field is 5-10 cm according to probe measurements CT Injec_on across transverse field
Cited In (1 references)
Research Rounds (1)
Frequently Asked Questions
What is this document? ▾
Researchers have developed a method to 'refuel' a fusion energy experiment by shooting high-speed plasma rings, called Compact Toroids, into a containment vessel. This technique successfully replenishes lost particles, helping to maintain the stability and density of the plasma needed for potential ...
Where does this document come from? ▾
The document was authored by Tadafumi Matsumoto of Nihon University (Japan) as part of a collaboration with the University of California at Irvine and Tri Alpha Energy. It was presented at the US-Japan CT2016 workshop.
What is the research purpose of this document? ▾
The research aimed to address the high particle loss rate in the C-2U Field-Reversed Configuration (FRC) fusion device by developing a Compact Toroid (CT) injector capable of penetrating the magnetic field to provide refueling.
Where is this document cited in the investigation? ▾
This document is referenced in 1 places across the investigation: 1 Research Rounds. See the "Cited In" section below for the complete list of pages that reference this document.