Angular distribution and polarization of atomic radiative emission in electric and magnetic fields

Journal Article · Wed Sep 01 00:00:00 EDT 1999 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.60.1975· OSTI ID:6469433

Jacobs, V L ^[1]; Filuk, A B ^[2]

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1. Center for Computational Materials Science, Code 6390.2, Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375-5345 (United States) Institute for Plasma Research, University of Maryland, College Park, Maryland 20742-3511 (United States)
2. Ion Beam Generation Department, Organization 9533, MS 1186, Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)

A density-matrix approach has been developed for the angular distribution and polarization of radiative emission during single-photon atomic transitions for a general set of steady-state excitation processes in an arbitrary arrangement of static (or quasistatic) electric and magnetic fields. Particular attention has been directed at spectroscopic observations in the intense fields of the high-power ion diodes on the Particle Beam Fusion Accelerator II (PBFA II) and SABRE devices at Sandia National Laboratories and at magnetic-field measurements in tokamak plasmas. The field-dependent atomic eigenstates are represented as expansions in a complete basis set of field-free bound and continuum eigenstates. Particular emphasis has been given to directed-electron collisional excitations, which may be produced by an anisotropic incident-electron velocity distribution. We have allowed for the possibility of the coherent excitation of the nearly degenerate field-dependent atomic substates, which can give rise to a complex spectral pattern of overlapping Stark-Zeeman components. Coherent excitations may be produced by a beam of electrons that are spin-polarized at an angle with respect to the propagation direction or by nonparallel electric and magnetic fields. Our main result is a general expression for the matrix elements of the photon-polarization density operator representing the total intensity, angular distribution, and polarization of the atomic radiative emission. For the observation of radiative emission in the direction of the magnetic field, the detection of linearly polarized emission, in addition to the usual circularly polarized radiation, can reveal the presence of a perpendicular electric field or a coherent excitation mechanism.

• OSTI ID: 6469433
• Journal Information: Physical Review A, Vol. 60:3; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ELECTRIC FIELDS
ELECTRO-OPTICAL EFFECTS
ELECTRON BEAMS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
MAGNETIC FIELDS
MAGNETO-OPTICAL EFFECTS
PHOTON-ATOM COLLISIONS
POLARIZATION
STARK EFFECT
ZEEMAN EFFECT
ATOM COLLISIONS
BEAMS
COLLISIONS
DISTRIBUTION
ENERGY LEVELS
LEPTON BEAMS
PARTICLE BEAMS
PHOTON COLLISIONS
664100* - Theory of Electronic Structure of Atoms & Molecules- (1992-)
664200 - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)