MOTION OF A CHARGED PARTICLE IN A NONADIABATICALLY VARYING MAGNETIC FIELD.

Experiments demonstrate that charged particles can be accelerated effectively in a homogeneous magnetic field which has an axisymmetric boundary and which increases over time in such a manner that the condition for adiabatic motion is seriously violated. The particle energy increases in proportion to the square of the magnetic field. When the field growth stops, the particles converge to the symmetry axis of the field, and this convergence is repeated at the gyrofrequency.