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Methods of generation of shock waves and measurement of gas-dynamic parameters in dynamic experiments
Published in G. I. Kanel′, Shock Waves in Solid State Physics, 2019
Most often, conic explosive lenses are used as plane-wave generators (Fig. 2.1), whose principle of operation is based on the use of elements with different detonation speeds. Such explosive lenses consist of an external conical explosive charge with a high detonation velocity and an inner explosive charge with a low detonation velocity (usually a mixture of barium nitrate with TNT – barathol) or inert material (usually lead or paraffin). High-speed detonation in the outer cone excites in the liner a detonation or shock wave inclined to form a cone at an angle φ defined by the ratio of wave velocities in the outer and inner elements: sin φ = Dliner/Dend. The aperture angle of the cone ψ is chosen such that a plane wave emerges at the base of the liner: ψ = π – φ.
The Trinity High-Explosive Implosion System: The Foundation for Precision Explosive Applications
Published in Nuclear Technology, 2021
Eric N. Brown, Dan L. Borovina
The explosive lenses concept employed two explosives with different detonation velocities. When a detonator creates a point initiation in the faster explosive, a nominally divergent spherical shockwave propagates out at constant velocity. If center lit on one end of a cylinder of constant cross section, the detonation will break out at the center of the other end before doing so at its circumference, consistent with the difference in distance to the initiation point. For implosion to work, the detonation wave needs to uniformly reach the inner surface (or the “tamper”) at the same time (see Fig. 9). By replacing some of the faster explosive with a slower detonation velocity explosive, the breakout time at a given point on the inner surface of the explosive can be designed based on the ratio of detonation velocities of the two explosives, and on the total length between the initiation point and the surface, to determine the ratio of lengths of fast and slow explosives required along that ray.