Most fusion machines bend their magnetic field into a ring, because a straight field leaks at its ends. Ours stays straight. A magnetic mirror at each end turns most of the ions back, and a hill of voltage turns back the rest.
The hill's height in units of the ions' temperature. The plant is designed for about 3.
1 · A straight field
A charged particle in a magnetic field circles a field line and slides along it freely. Sideways it hardly moves, so the field holds the plasma away from the wall. Along the line nothing stops it. In a straight field every ion runs out of an end on its first pass.
2 · The mirror
Stronger coils at each end squeeze the field lines together. An ion running into the squeeze trades speed along the line for speed around it, slows, and turns back. Ions moving too nearly along the line get through: they escape inside a cone of directions, the loss cone. Collisions between ions keep knocking more of them into it.
3 · The plug
At each end the voltage rises above the plasma's. An ion in the loss cone now has to climb the hill as well, and only the fastest few can. In this simulation each rise of one ion temperature cuts the leak about 2.7 times, and at the plant's height the leak is about a twentieth of the mirror's alone. Move the hill and watch the cone.
The hill would draw the plasma's electrons to it and cool, so just inside it a dip in voltage, the thermal barrier, keeps the two groups of electrons apart.
Live: 500 ions, computed in your browser. Not to scale: in the plant an ion's circle is a few centimetres across, in a plasma 2.25 m wide and 401 m long.
4 · The plant
The ends take about the same power however long the middle is, and the fusion power grows with the length. So the middle is long: a row of identical magnet modules, designed to be made in our own factories and joined on site.
The plant as designed on 3 Nov 2026, from our design record: model readings. Nothing has been built yet.
5 · How we design it
Each figure in the design carries its source: a measurement, a published law, a derivation, a simulation we have checked against real machines, or an assumption we still have to remove. The price of electricity is computed from the physics of every part, so a change to any part shows up in the price.
We write down what our models predict for other machines before we read those machines' data. Ten such predictions are on record. Four have been scored so far: one held and three missed, and the misses stay on the record.
The formulas the design rests on are proved as theorems and checked by computer: 10,232 of them, as built on 2 Nov 2026.
Status A design. Nothing has been built yet.
For our team and investors
Investors see our investor presentation. Our team sees the full design, part by part, and builds it here.
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