Investigation of capabilities of multibeam interferometry in monitoring of the parameters of laser fusion targets

A study was made of the use of multibeam interferometry methods in monitoring the parameters of laser fusion targets and their capabilities were estimated. Elimination of the influence of diffraction made it possible to reduce the error in the determination of the fringe shift by oscillographic recording to ΔN = ±1/300 of a fringe. This error made it possible to detect variations of the wall thickness of a shell target (microbubble) to within Δd = ±2nm, which in the case of a wall of thickness d~1μ corresponded to Δd/d = ±0.2%. In measurements of the gas pressure in a shell target the error in the determination of the fringe shift amounting to 1/300 of a fringe gave rise to a gas pressure error of Δp = ±0.1 atm for shells ~150 μ in diameter.