الفهرس 
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Abstract
Nuclear electromagnetic pulse (NEMP) is a high amplitude short duration electromagnetic pulse that originates from a nuclear burst. The high altitude EMP results due to the gamma radiation following the strong nuclear burst which causes atmospheric electrons to be freed, which in turn generate the EMP during their motion under the effect of the earth’s magnetic field. The level of the resulting electric field is about 50 kV/m with a rise time of a few nanoseconds. The effects of EMP extend to an area of 500-800 km or even more in radius depending on the height and the power of burst. Its spectrum is concentrated below 100 MHz. Any conductor within the affected area of EMP will act as an antenna to pick up the electromagnetic pulse .The induced currents and voltages may cause malfunction or damage of electronic equipment within the affected area. It should be noted that there are types of EMP such as that resulting from near surface and under ground explosions. Emphasis in this thesis, however is high altitude EMP. In the present work the basic aspects of the NEMP are presented including its generation, the characteristics of the EMP, its penetration into electronic systems, and the protection methods against EMP. The penetration of EMP into a shielded cavity is investigated using FDTD method .The characteristic of the penetrating field is studied under different conditions. The current induced in a wire located inside a cavity is also calculated. The thesis comprises four chapters followed by a conclusion as follows.