Plasma motion across a magnetic field

We discuss a simple model of a neutralized ion beam propagating across an applied magnetic field by means of an E x B drifting motion. The electric field is produced by the polarization of the beam due to the different ion and electron orbits in the magnetic field. The plasma can cross the field if ω/sub π/2 >> Ω/sub i/2, where ω/sub π/ is the ion plasma frequency and Ω/sub i/ is the ion gyrofrequency. If ω/sub π/2 << Ω/sub i/2, each plasma particle penetrates the field a distance equal to its own gyroradius, and is then reflected