Imaging of high-power microwave-induced surface flashover

Using two gated intensified digital charge-coupled device cameras, one sens itive in the near infrared to ultraviolet region and one in the soft X-ray region, the temporal development of high-power microwave-induced surface fl ashover across a vacuum/dielectric interface has been imaged. The emission of X-ray radiation from the interface is caused by field emitted electrons accelerated in the high electromagnetic field impacting the solid. This gen eration of bremsstrahlung terminates at the moment of full flashover develo pment that is indicated by the optical light emission. A rising plasma dens ity above the dielectric surface due to electron induced outgassing trigger s this behavior.