Physics

Tokamak

Plasma in a toroidal magnetic cage on the Boris pusher.

Actual application image

What happens

Thousands of charges ride the exact Boris pusher in a 1/R toroidal field. Turn the plasma current OFF and watch the textbook failure live: drifts separate the charges and the plasma rains onto the wall - the reason tokamaks twist their field lines into helices. Turn it back on and the same plasma sits in the cage.

Equations used in the module

Equations
m dv/dt = q (E + v × B)   (Boris pusher: |v| exact in B)
B_toroidal ∝ 1 / R,   B_poloidal from the plasma current
q = r B_t / (R B_p)   (safety factor);  no current, no confinement

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