The steady-state bistability and the evolution of the field envelope of a ring-cavity optical-bistable system including the effect of the transverse radiation field and the effect of an inhomogeneously broadened atomic medium are studied by means of the mean-field approximation and dressed-mode theory in this paper. Our study shows that the bistable region enlarges with an increase of the ratio r0/w0 (r0 is the radius of the cylindrical atomic sample and w0 the beam waist of the Gaussian beam), and decreases with increasing width of the inhomogeneously broadened line. The transverse-field effect has more impact on the magnitude of the bistable region than the inhomogeneous broadening under certain conditions. In the case of two unstable modes, the evolution of the field envelope before reaching the stable oscillation regime differs remarkably from that in the case of the plane-wave approximation with a homogeneously broadened atomic medium.

Sever and Tezcan recently [Phys. Rev. A 36 (1987) 1045], used the 1/N expansion to solve the time independent Schrodinger equation with a more general screened Coulomb potential; V (r) = -(a/r) [1 + (1 + br)exp(-2br)] obtained the analytical expressions, and gave some numerical values of energies for 1s and 2s states. We apply the shifted 1/N expansion to solve the same Schrödinger equation and calculate the numerical values of energies for 1s to 5g states. Our results for 1s and 2s states are excellent agreement with those obtained by solving the Schrodinger equation by means of the numerical calculation method, and the accuracy is much better than the results of Sever and Tezcan.

In recent years ion traps of various types have served in studies of collision interactions and spectroscopy of low energy multicharged ions. With large storage rings for multicharged heavy ions, dedicated to atomic physics research, now planned or coming into operation, it is useful to consider the role of ion traps in future experimental work. The capabilities and current limitations of multicharged ion research using traps are discussed, and a comparison with storage rings for the purposes of ion spectroscopy is made. Recent experimental investigations to develop techniques for the study of multicharged ions in traps using laser or synchrotron radiation are discussed, including a UHV pulsed gas source and an atom beam as ionization targets.