Radiative cascade between Rydberg atomic states

A analytic solution is obtained- for two-dimensional (in principal n and orbital l quantum number space) radiative cascade between Rydberg atomic states. It is shown that under conditions of validity of the Bethe rule for radiative transition probabilities, the cascade population of twe tevets is determined by the prrely classical mechanism of ''flow'' of the electron fluid in nl space due to classical energy and momentum losses as a result of radiation emission. The regions in nl space in which the electron motion is that of quantum jumps and the regions in which the motion is of the classical continuous nature are investigated. An algorithm for calculation of the cascsde in the generai quantum case is presented which is based on the quasiciassicai method of summation of terms in a cascade matrix. Concrete calculations of the populations for a photorecombination source are carried out which are in good agreement with the numerical quantum calculations even in the region of small n and l values. The scaling parameters for the populations are found. The calculations show that a strong difference exists between the population and the distribution of the statistiacal weights, particularly in the low temperature region