Search for Exotic Shapes in Liquid-Drop Collisions

We are engaged in establishing a bridge between fields where macroscopic liquid-drop collisions are important and heavy-ion reaction modeling, particulary with those theories in which the quantal effects can, somehow, be switched off, allowing a direct access to the bare liquid-drop aspects. Besides providing an interesting testing-ground for those sophysticated models, this represents the oportunity of applying them to fields like meteorology and spray research, where the theoretical situation is less developed. On the 10th Winter Workshop on Nuclear Dynamics, in 1994, we presented [1] the results of collision experiments using mercury drops with the hope of gaining the interest of theoretical nuclear dynamisists. As a result, a collaboration was indeed established which lead to the modification of a nuclear reaction code, developed by N. Cârjan, A. Sierk and R. Nix [2] allowing the simulation of macroscopic liquid-drop collisions. Here we like to make a brief review of what we have learned so far in this line of research. A subject which recently cought our attention was the predictions [3] of nuclear fluid-dynamic simulations concerning the posibility of multifragmentation mechanisms proceeding via the formation of exotic nuclear shapes (sheets, bubbles, donuts, etc.) Since similar predictions have also been reported for macroscopic systems [4] we are now experimenting with liquid-drops colliding at the relative velocities where those exotic shapes are expected [4] to appear. This presentation will also include the first results of that quest, including interesting video images.