Direct-Drive Irradiation Uniformity for the NIF
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چکیده
In this article, we first address how the indirect-drive irradiation geometry must be modified to accommodate direct drive. Emphasis is placed on finding an acceptable direct-drive geometry that minimizes the amount of reconfiguration. Tolerances for energy imbalance, beam mispointing, and target-positioning errors are discussed for the proposed irradiation geometry. The beam uniformity that can be achieved using 2-D SSD is alsoexarnined. One related laser design issue that affects the level of uniformity is pinhole size. The pinholes determine the maximum amount of angular spectral dispersion that can be used with SSD. The dependence of uniformity on pinhole size is discussed. Finally, the SSD-smoothed beam profile is combined with the direct-drive bearn geometry to calculate the irradiation unil'orniity on a spherical target with multiple overlapping beams.
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