Joint European Torus

also JET

The main purpose of JET is to test plasma physics, systems and materials for ITER, and to study plasma behaviour in conditions and dimensions close to those of a fusion power plant.

Operator: UK Atomic Energy Authority
Type: Fusion device
Approach: Tokamak
Fuel: D-T
Country: GB
Status: Decommissioned
Built: 1983
Ownership: public

Progression

59 MJ 2021-12-21
→
69.26 MJ 2023-10-03

Results

69.26 MJ Fusion energy yield achieved

measured 2023-10-03 · shot 104522 · high confidence

59 MJ Fusion energy yield superseded

measured 2021-12-21 · shot 99971 · medium confidence

6.1 × 10²⁰ m⁻³·keV·s Fusion triple product (nTτ_E) claimed

measured 1991-11-02 · shot 26087 · medium confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

18.6 keV Ion temperature claimed

measured 1991-11-02 · shot 26087 · peak · medium confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

4.1 × 10¹⁹ m⁻³ Plasma density claimed

measured 1991-11-02 · shot 26087 · medium confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

0.8 s Energy confinement time (τ_E) claimed

measured 1991-11-02 · shot 26087 · medium confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

0.63 Plasma gain (Q_plasma) claimed

measured 1997-10-31 · shot 42976 · Fusion power produced ÷ External heating power coupled into the plasma · high confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

0.33 Plasma gain (Q_plasma) claimed

measured 2021-12-21 · shot 99971 · average · Fusion power produced ÷ External heating power coupled into the plasma · high confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

0.37 Plasma gain (Q_plasma) claimed

measured 2023-10-03 · shot 104522 · average · Fusion power produced ÷ External heating power coupled into the plasma · high confidence

Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria independent

Design values

What the machine was built to do, as published. Not results, and never ranked.

Design values for Joint European Torus
Parameter	Value	Unit	Status	Source
Major radius medium confidence	2.96 m	m	claimed	World Survey of Fusion Devices 2022 independent
Minor radius medium confidence	1.25 m	m	claimed	World Survey of Fusion Devices 2022 independent
Plasma current medium confidence	5 MA	MA	claimed	World Survey of Fusion Devices 2022 independent
On-axis magnetic field medium confidence	3.4 T	T	claimed	World Survey of Fusion Devices 2022 independent
Plasma duration (nominal) medium confidence	60 s	s	claimed	World Survey of Fusion Devices 2022 independent