NDLI: Formation of the 0.511.-mev line in solar flares. [statistical mechanics of line spectra for gamma rays

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Formation of the 0.511.-mev line in solar flares. [statistical mechanics of line spectra for gamma rays

Content Provider	NASA Technical Reports Server (NTRS)
Author	Joyce, G. Ramaty, R. Crannell, C. J. Werntz, C.
Copyright Year	1976
Description	The gamma-ray line produced at 0.51-MeV was studied and is shown to be the result of either of free annihilation of positrons with electrons or of the decay of positronium by 2-photon emission. Positron annihilation from the bound state of positronium may also proceed by 3-photon emission, resulting in a continuum with energies up to 0.51-MeV. Accurate calculations of the rates of free annihilation and positronium formation in a solar-flare plasma are presented. Estimates of the positronium-formulation rates by charge exchange and the rates of dissociation and quenching are also considered. The temperature and density dependence of the ratio of 3-photon to 2-photon emission was obtained. It is shown that when the ratio of free electrons to neutral atoms in the plasma is approximately unity or greater, the Doppler width of the 0.51-MeV line is a function of the temperature of the annihilation region. For the small ion densities characteristics of the photosphere, the width is predominantly a function of the density.
File Size	20230759
Page Count	48
File Format	PDF
Alternate Webpage(s)	http://archive.org/details/NASA_NTRS_Archive_19760010941
Archival Resource Key	ark:/13960/t4zh1dq10
Language	English
Publisher Date	1976-01-01
Access Restriction	Open
Subject Keyword	Solar Physics Gamma Rays Charge Exchange Solar Flares Plasmas Physics Maxwell-boltzmann Density Function Photons Positronium Positron Annihilation Line Spectra Statistical Mechanics Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science
Content Type	Text
Resource Type	Article

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