We investigate the effects of quickly creating a plasma around a monochromatic electromagnetic source wave, on time scales on the order of a cycle of the wave. It is found that this results in an upward shifting of the wave frequency, which can be varied by changing of the plasma density. It is also found that a substantial fraction of the magnetic field associated with the initial wave can be sustained in the plasma as a time-independent magnetic field. Computer simulations have been used to study this process in detail, including the effects of finite ionization time. For long ionization times, strong plasma heating results.

• Received 8 February 1988

DOI:https://doi.org/10.1103/PhysRevLett.61.337