The success of direct drive laser fusion depends upon the capability of illuminating spherical targets with an overall uniformity of ~1 %. Approaches so far taken to achieve this high degree of irradiation uniformity include the use of ultrahigh-power reflective clamshell optics, multiple-beam irradiation, and multiple-multiplexed beam illumination. In addition to the basic irradiation geometry utilized the irradiation uniformity is also dependent on the radial intensity profile of each beam incident on target, the refraction of light rays in the underdense plasma surrounding the target, and the mechanism of absorption.

© 1983 Optical Society of America

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