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

Abstract

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 polarizationmore » 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.« less

Authors:
 [1];  [2]
  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))
Publication Date:
OSTI Identifier:
6469433
Alternate Identifier(s):
OSTI ID: 6469433
Resource Type:
Journal Article
Journal Name:
Physical Review A
Additional Journal Information:
Journal Volume: 60:3; Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
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-)

Citation Formats

Jacobs, V.L., and Filuk, A.B. Angular distribution and polarization of atomic radiative emission in electric and magnetic fields. United States: N. p., 1999. Web. doi:10.1103/PhysRevA.60.1975.
Jacobs, V.L., & Filuk, A.B. Angular distribution and polarization of atomic radiative emission in electric and magnetic fields. United States. doi:10.1103/PhysRevA.60.1975.
Jacobs, V.L., and Filuk, A.B. Wed . "Angular distribution and polarization of atomic radiative emission in electric and magnetic fields". United States. doi:10.1103/PhysRevA.60.1975.
@article{osti_6469433,
title = {Angular distribution and polarization of atomic radiative emission in electric and magnetic fields},
author = {Jacobs, V.L. and Filuk, A.B.},
abstractNote = {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.},
doi = {10.1103/PhysRevA.60.1975},
journal = {Physical Review A},
issn = {1050-2947},
number = ,
volume = 60:3,
place = {United States},
year = {1999},
month = {9}
}