(a) Waveforms of the discharge currents and resistive voltages; (b)power and deposited energy into the ring-shape wires.
Image of ring holder with a ring-shaped wire. The ring's diameter is ; it is made of Cu wire with a diameter of
Overlaid multi-frame image from the 4QuikE fast framing camera of the TOF experiments. Left—original image, right—same image with SW fronts marked for brevity, with the distances from the implosion axis.
Optical setup for simultaneous shadow and Schlieren imaging. 1—CW 532 nm dc laser; 2,3,4—1 in. flat mirrors; 5—photodetector; 6—pulsed 532-nm laser; 7—transparent parallel plate; 8—diaphragm; 9—negative lens; 10—ND filter; 11—2 in. flat mirrors; 12—windows in the experimental chamber; 13—experimental chamber; 14—load (straight wire or wire-ring); 15—objective lenses; 16—narrowband filter (full width at half height is 10 nm); 17—beam-splitter; 18—Canon CCD camera; 19—knife; 20—Nikon D60 CCD camera.
A sample image of an annular SW in a misaligned optical configuration, taken by a CCD camera body.
Schlieren (a) and shadow (b) images of the imploding annular SW obtained with CCD cameras. The images were taken simultaneously at , with zoom ∼1:1. The radius of the undisturbed water is . 1—undisturbed water area; 2—the shock wave front region with the highest refraction index; 3—water flow behind the shock wave; 4—expanded plasma channel of the exploded wire material.
Zoomed (∼1:5) shadow images of an imploding annular SW. (a)Elliptical form with large and small radii of ∼40 and ∼25 μm, respectively; (b) non-uniform front of the SW at radius of ∼17 μm.
Measurements of the radius of the annular shock wave front as a function of time. The data are incorporated from both the 4Quik fast framing camera (squares) and the CCD camera images (circles). The typical error of the 4Quik camera images is 150 μm, and 5 μm of the CCD images. The dashed curve is the result of a calculation based on the acoustic approximation. 14
Side-view 1:1 shadow image of an imploding annular SW at time delay of with respect to the beginning of the discharge current.
Out-of-scale schematics of annular SW in water. (a) TSW at some early time. The arrows show the principal directions of the curvatures. (b) TSW during the “leading edge” development, when the radius of its convex curvature is not equal to its width. On both images—the transformation of a dark surface element during the TSW convergence.
Cross-section of the leading part of the TSW in the roz plane. Note the fanning-out of the water flow as it passes through the TSW front. A symmetric fanning-out is obtained in the upper part.
Annular SW cross-sections at different times prior to implosion: left— ; right— . The circles denote the shock wave's curvature.
Article metrics loading...
Full text loading...