ABSTRACT
A remarkable property of magnetic fields may be the key to the problem of fusion plasma confinement, namely the fact that free motion of charged particles is not allowed in directions transverse to the magnetic field. Instead, the particles will spiral around the magnetic field lines. The radius of the spiral, the Larmor radius, is proportional to the square root of the thermal energy and inversely proportional to the magnetic field. For typical tokamak ion temperatures T — 10 keV and magnetic fields В = 5 T the ion Larmor radius is less than a centimetre.
