Multiple-photon Compton scattering in a strong magnetic field: Cross-sections and radiative transport
Astrophysical plasmas in the vicinity of a neutron star are believed to be threaded by a strong magnetic field. The physics of electron-photon scattering in such a field is investigated quantum electrodynamically, and calculations of the cross sections reveal that one-photon Compton scattering is the dominant process for photon energies in the continuum and near the fundamental cyclotron harmonic. The presence of the strong field permits two multiple photon processes that are analytically of the same order in the fine structure constant as one-photon scattering, and these are shown to dominate near the higher cyclotron harmonics. These processes are two-photon scattering where the electron is scattered into an excited state from which it radiatively decays with the emission of a second photon; and two-photon emission where an electron cyclotron absorbs a photon and then decays to the ground state with the emission of two photons. Since several of the terms that describe the two-photon processes in the differential equation of radiative transport are nonlinear, the discrete ordinate finite difference Feautrier method is extended to include nonlinear effects. This technique is used with the one- and two-photon processes to calculate model spectra that extend to the higher cyclotron harmonics for x ray pulsars and gamma ray bursters. The x ray pulsar model is a self-radiating optically thick slab, and the results show general agreement with observations of Hercules X-1. The model for the hard x ray spectrum of gamma ray bursts consists of radiation that is transmitted through an optically thin sheet of plasma. The results give excellent agreement with observations of the gamma ray burster GB 880205.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (USA). Davey Lab.
- OSTI ID:
- 5977097
- Resource Relation:
- Other Information: Ph.D. Thesis
- Country of Publication:
- United States
- Language:
- English
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GENERAL PHYSICS
PHOTON-ELECTRON INTERACTIONS
COMPTON EFFECT
CROSS SECTIONS
COSMIC GAMMA BURSTS
CYCLOTRON RADIATION
DIFFERENTIAL EQUATIONS
EXCITATION
FINE STRUCTURE
FINITE DIFFERENCE METHOD
HARMONICS
MAGNETIC FIELDS
NEUTRON STARS
PLASMA
PULSARS
STAR MODELS
THEORETICAL DATA
BASIC INTERACTIONS
BREMSSTRAHLUNG
COSMIC RADIATION
COSMIC RADIO SOURCES
DATA
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
EQUATIONS
INFORMATION
INTERACTIONS
IONIZING RADIATIONS
ITERATIVE METHODS
MATHEMATICAL MODELS
NUMERICAL DATA
NUMERICAL SOLUTION
OSCILLATIONS
PARTICLE INTERACTIONS
PHOTON-LEPTON INTERACTIONS
PRIMARY COSMIC RADIATION
RADIATIONS
SCATTERING
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources