Multicolor detachment of a negative ion in the presence of a static magnetic field

The photodetachment of a negative ion by a weak electromagnetic field, with a frequency near the photodetachment threshold, in the presence of a stati c magnetic field and a low-frequency (LF) bichromatic electromagnetic field , whose components have commensurate frequencies, is investigated. The case is treated in which the ejected electron may exchange a large number of ph otons of the LF field. It is found that when the relative phase of the LF f ield components is zero, the photoelectron flux along the magnetic held in the forward direction is different from the one in the backward direction. Moreover, the case is addressed in which the photodetachment is caused by t he action of two weak fields whose frequencies differ by a small integer mu ltiple of the frequency of a monochromatic LF assisting field, in the regim e in which the cyclotron frequency is a multiple of the frequency of the LF field.