The Calculation Of Lower Bounds On The Breakdown Power Levels Of Electromagnetic Structures

The prediction of the power level at which a plasma-covered antenna will break down is most difficult. Yet the problem is of crucial importance for all reentry vehicles and especially for ECM vehicles which must operate at high power levels for jamming purposes. Recently variational techniques have been applied to estimate breakdown power levels. These techniques have one drawback in that only upper bounds are provided, that is, the power level above which breakdown definitely takes place. Depending on the accuracy of a particular calculation, breakdown may occur for an appreciable power range below the estimated level. What is needed is a lower bound on the breakdown field strength. In the report a formulation of variational theory is given which allows lower bounds to be calculated. (Author Modified Abstract).