Abstract
We investigate the classical dynamics of the problem of two centers and a finite dipole by means of a common Hamiltonian model. Conditions for trapped orbits are determined first by a qualitative analysis of the effective potential, revealing two types of bifurcation in the two-center problem as a control parameter passes through a critical value . For equal masses there is a pitchfork bifurcation, for unequal masses a tangent bifurcation. Separating the common Hamiltonian in elliptic coordinates shows that the third invariants for the two-center problem and the finite dipole are isomorphic in scaled variables. Explicit trapping conditions are then found in terms of the coefficients of two quartics. A critical-point analysis for the finite dipole shows that a potential well exists for all values of scaled angular momentum below the same critical value , at which the elliptic point runs off to infinity. In this case the existence of the third invariant does not confine any orbits not already trapped by energy conservation. A similar analysis of the effective potential for the point dipole shows that the only trapped orbits besides those impacting the origin are unstable zero-energy trajectories lying on a sphere.
- Received 12 June 1995
DOI:https://doi.org/10.1103/PhysRevA.52.4471
©1995 American Physical Society