Multigroup representation of fusion product orbits in a plasma column

Abstract

A method is derived for describing the time-dependent behavior of α particles produced in a radially nonuniform slender plasma column as a distribution function among the possible orbits. A multigroup numerical approximation is introduced to analyze the development of the distribution function and its moments. Results are presented of calculations of the time-dependent α-particle energy spectrum and radial density, energy, and electron heating profiles in plasma columns with radii comparable to the α Larmor radius. This technique allows calculation of the α particle history at much more rapid rates than allowed by Monte Carlo techniques: The characteristic time scale is the α-electron slowing-down time rather than the cyclotron period.