Lawson Criterion (Fusion)

n T \tau > 3 \times 10^{21} \text{ keV·s/m}^3

Fusion breakeven requires sufficient plasma density, temperature, and confinement time triple product.

By John Lawson

Frontier Sciences

1955 · John Lawson

Why it matters: Set the target for ITER, NIF, and commercial fusion ventures.

Discoverers: John Lawson (1955)

What does it mean?

Fusion breakeven requires sufficient plasma density, temperature, and confinement time triple product.

Set the target for ITER, NIF, and commercial fusion ventures.

Symbol	Name	Unit	Meaning
$n$	Density	m⁻³	Plasma ion density
$T$	Temperature	keV	Plasma temperature
$τ$	Confinement time	s	Energy confinement

NIF 2022 achieved ignition; ITER targets Q>10.

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n T \tau > 3 \times 10^{21} \text{ keV·s/m}^3

Real-world impact

Space systems

Orbital mechanics enables global connectivity and exploration.

Photo: Unsplash — rocket launch

Fusion breakeven requires sufficient plasma density, temperature, and confinement time triple product.

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