Electron dynamics in parallel electric and magnetic fields

Abstract

We examine the spatial distribution of electrons generated by a fixed energy point source in uniform, parallel electric and magnetic fields. This problem is simple enough to permit analytic quantum and semiclassical solution, and it harbors a rich set of features which find their interpretation in the unusual and interesting properties of the classical motion of the electrons: For instance, the number of interfering trajectories can be adjusted in this system, and the turning surfaces of classical motion contain a complex array of singularities. We perform a comprehensive analysis of both the semiclassical approximation and the quantum solution, and we make predictions that should serve as a guide for future photodetachment experiments.Comment: 24 pages,12 figure

Propagation of charged particle waves in a uniform magnetic field

“…More recently, a similar analysis was performed for the case of parallel electric and magnetic fields. The simultaneous action of both forces leads to more complex trajectory fields with an adjustable number of interfering paths, and correspondingly more involved interference patterns that are nevertheless in excellent agreement with the exact quantum solution [40][41][42]. First experimental images of the electron distribution observed in photodetachment in parallel fields have recently become available [43].…”

“…In his paper, Berry [44] predicted the amplification of the electron waves near the caustics, but stopped short of calculating the electronic wave function itself. Our aim here is to systematically examine the properties of the electron wave from a classical, semiclassical, and quantum mechanical perspective, following the leads of a former study of the parallel field configuration [42]. We find that much of the added complexity in the magnetic case owes to the fact that the electron now can travel (if at all) along an infinite number of different classical paths from the source to any given destination, and that the electron drifts without acceleration along the magnetic field direction B.…”

Photodetachment electron flux of H− in combined electric and magnetic fields with arbitrary orientation

“…In the theoretical aspect, because Du's semi-classical theory provide a vivid physical picture description of the photodetachment process of negative ion in external fields [1], many researchers have used his semi-classical method to treat some more complicated systems. In 2006-2007, Bracher and Delos studied the detached electron dynamics in parallel electric and magnetic fields [11,12]; Gao et al calculated the electron flux distribution of H − in parallel electric and magnetic fields [13]. Recently, Tang and Wang studied the photodetachment microscopy of H − in an electric field or in a magnetic field near a surface [14,15]; Bracher and Gonzalez studied the electron dynamics in a uniform magnetic field [16].…”

Interference of the photodetached electron waves propagating in perpendicular electric and magnetic fields

“…Du's study opened a new method for studying the photodetachment microscopy theoretically. Later, many researchers have used this semi-classical method to treat the detached electron's dynamics in different external fields, such as in parallel electric and magnetic fields [11][12][13]; in electric field or magnetic field near a surface [14][15][16][17]; in a uniform magnetic field, [18] in crossed electric and magnetic fields. [19] Unlike the case of the electron photodetached from H − ion in an electric field, where only two detached electron's trajectories emitted from the source negative ion can arrive at a same point on the detector plane.…”