A method and apparatus is provided for generating a plasma electron flood using microwave radiation. In one embodiment, a microwave PEF apparatus is configured to generate a magnetic field that rapidly decays over a PEF cavity, resulting in a static magnetic field having a high magnetic field strength near one side (e.g., “bottom”) of the PEF cavity and a low magnetic field strength (e.g., substantially zero) near the opposite side (e.g., “top”) of the PEF comprising an elongated extraction slit. In one particular embodiment, the one or more permanent magnets are located at a position that is spatially opposed to the location of the elongated extraction slit to achieve the rapidly decaying magnetic field.The magnetic field results in an electron cyclotron frequency in a region of the cavity equal to or approximately equal to a microwave radiation frequency so that plasma is generated to diffuse through the extraction apertures.