We have demonstrated that the boundaries separating the basins corresponding to the various exit modes in a typical chaotic scattering system may not only be fractal, but they may also possess the stronger Wada property. We conjecture that the existence of Wada basin boundaries is a common occurrence for chaotic scattering systems with multiple exits.
As pointed out in Bleher et al. [1988], physical situations where the above results might be relevant can be found in space physics. In addition to the examples cited in Bleher et al. [1988], we mentioned two more cases. In a study on gravitational scattering of a single star by a rotating binary star system [Boyd & McMillan, 1992], it is found that there are several ways or ``exits'' in which the system can end up. After the incident star interacts with the binary system in a complicated manner, one star eventually gets ejected from the system, but which one escapes is sensitively dependent on the initial conditions. Another example where our results are of interest is the motion of charged particles in Earth's magnetosphere. It has been shown in Chen et al. [1990] and Chen [1992] that there are various ways in which the charged particles that was originally confined to the magnetotail (a region of the Earth's magnetosphere) can escape, and the basins corresponding to these different ``exits'' are separated by fractal basin boundaries. With some work, it seems probable that some of these systems can be shown to possess Wada basin boundaries.
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