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For K-12 Students · Fusion (Lawson)

Fusion (Lawson) for a radiotherapy beam

Built for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework. Simulate a radiotherapy beam live below — adjust the inputs and watch it respond, right in your browser.

Fusion (Lawson Criterion)Live

the recipe for a star on Earth

Controls

Presets

Density (10²⁰ /m³)

Confinement time (s)

Temperature (keV)

To get more fusion energy out than you put in, a plasma must be hot enough, dense enough, and confined long enough — captured together in the triple product n·τ·T. The Lawson criterion sets the threshold for ignition, where the fusion self-heats. Crossing it, at over 100 million degrees, is the decades-long goal of tokamaks and laser fusion.

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Data Inspector

Triple product1.50e+21

Fraction of ignition50%

Statussub-ignition

Governing equation

n τ_{E} T = 1.5 e + 21 < 3 \times 1 0^{21} keV\cdots\cdotm^{- 3}

Reading this result: Sub-ignition at 50% — the plasma leaks heat faster than fusion replaces it, so raise density, confinement time, or temperature to close the gap.

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Frequently asked questions

Is this good for k-12 students?: Yes — this version of "Fusion (Lawson) for a radiotherapy beam" is framed for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.