Magnetic Confinement
8 min read · Energy Atlas Editorial
Charged particles follow magnetic field lines. Tokamaks and stellarators twist those lines into a torus so plasma cannot leak out too quickly.
A straight magnetic solenoid leaks particles at both ends. Bending the field into a torus removes the ends, but a purely toroidal field is stronger on the inside of the doughnut. Particles then drift vertically and the plasma polarizes. The fix is to twist the field lines helically so particles sample both the strong-field and weak-field sides.
Tokamaks create much of that twist with plasma current. Stellarators build the twist into the coils. Both are magnetic confinement; they differ in how they produce rotational transform.
Keep reading
Articles
Tokamaks
The word "tokamak" is of Russian origin and means "toroidal chamber and magnetic coils." This magnetic confinement system holds plasma in magnetic fields of toroidal shape. The first tokamak, the T-1, started operation in 1958 in Russia, and since then the greatest advances in th
16 min read
Stellarators
Stellarators are "generators of stellar energy", and their principle was discovered before tokamaks. A helical-twisted magnetic field, necessary for successful plasma confinement, is generated only by magnetic coils of various shapes. The stellarator is a device capable of contin
14 min read
Plasma
To enable thermonuclear fusion, the matter has to be heated to several million kelvin. But what will happen to such incredibly hot substances?
5 min read
Questions
Tokamak or stellarator — what is the difference?
Both confine plasma in a torus. Tokamaks use plasma current; stellarators use twisted coils.