NEUTRON PRODUCTION BY FUSION IN A CLASS OF ANISOTROPIC PLASMAS.
Abstract
The neutron production rate of a fusion reaction in a plasma of deuterium is calculated by a non-Maxwellian average, assuming the differential cross section is known. For the average it is assumed the ion velocity distribution of one plasma component is that of a beam and that of the other component is a Maxwell distribution. It is found that cross section anisotropy has no effect on neutron production rate or on the excitation function. An expression is obtained which contains the detailed effects of anisotropy on neutron speed and angle distributions. Prominent behavior of this expression is discussed. For purposes ofnumerical calculation, a Gamow form is assumed for the total cross section. Neutron production rate results are presented in a contour plot as a function of beam energy and plasma temperature over ranges of the parameters of most interest in thermonuclear research. Prominent behavior here is understood in the light of two well known subcases of this calculation: (1) neutron production by bombarding a cold target and (2) neutron production from a Maxwellian plasma. A qualitative analysis with order of magnitude estimates is made to consider the practical implications of the use of the assumed nonequilibrium distribution. It is shown that the assumed distribution may exist for small observation volumes and for short observation times in plasma regimes of thermonuclear interest. It is a general result of this analysis that an arbitrary plasma cannot be shown isotropic except by fine time resolution technique. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1966
- Accession Number
- AD0639658
Entities
People
- J. B. Langworthy
Organizations
- United States Naval Research Laboratory