Strongly Magnetized Antihydrogen and Its Field Ionization

Internal orbits of experimentally analyzed antihydrogen ($\overline{\mathrm{H}}$) atoms depend as much on an external magnetic field as on the Coulomb force. A circular “guiding center atom” model is used to understand their field ionization. This useful model, assumed in the theory of three-body $\overline{\mathrm{H}}$ recombination so far, ignores the important coupling between internal and center-of-mass motion. A conserved pseudomomentum, effective potential, saddle point analysis, and numerical simulation show where the simple model is valid and classify the features of the general case, including “giant dipole states.”