Atoms in strong magnetic fields

Recent results of investigations of hydrogenlike systems at magnetic field strengths where the Lorentz forces are comparable to, or larger than, the Coulomb binding forces are reviewed. Results for the wavelength spectrum of the hydrogen atom in magnetic fields of arbitrary strength are presented, and the way the unraveling of this spectrum has laid the foundation for a new branch of stellar atomic spectroscopy is described. Atoms in terrestrial laboratories are examined, discussing the progress that has recently been made in the theoretical description of magnetized Rydberg atoms. Spectroscopic predictions of theory are compared with experimental results, and it is demonstrated that phenomena which have turned out characteristic of the onset of 'quantum stochasticity' in investigations of model Hamiltonian systems are recovered in the quantal energy spectra of magnetic Rydberg atoms.