Compression and burning of a direct-driven thermonuclear target under the conditions of inhomogeneous heating by a multi-beam megajoule laser

The paper is devoted to the numerical and theoretical study of compression and burning of a thermonuclear target under the conditions of inhomogeneous heating due to direct irradiation with a multi-beam megajoule laser facility. The two-dimensional distribution of absorbed laser energy has been numerically calculated taking into account refraction and various known factors of the violation of irradiation homogeneity. The limits of the violation of irradiation uniformity caused by these factors, which are acceptable for spark ignition of the target irradiated with 192 laser beams of the modern megajoule facilities, are determined. The target offset relative to the aiming point of the laser beams should not exceed 2% of the target radius, mispointing of the beams (5% of the target radius), mistiming of the laser pulses (3% of the pulse duration) and energy imbalance among the laser clusters (12%). These values exceed the permissible deviations for the laser facility being developed within the frameworks of the project.