Scattering from density and magnetic fluctuations in a tokamak

Summary form only given. It is pointed out that all previous α particle diagnostic calculations of the scattering function S(k,ω) have been based on scattering of an incident electromagnetic wave from thermal fluctuations. Moreover, these earlier calculations did not take into account plasma or magnetic inhomogeneities. Here, the effects of both plasma and magnetic field inhomogeneities are included by resorting to a ray-tracing formalism. To leading order, one obtains information only on the propagation path of the millimeter radiation through the toroidal plasma. To obtain information on S(k,ω) one must proceed to the next order in which wave energy densities are considered. An integrodifferential wave kinetic equation for scattering of millimeter radiation from density and magnetic fluctuations was developed. This equation will be solved by appropriately modifying the Monte Carlo computer code of Bonoli and Ott (1982). Following a ray trajectory, the position of a Lagrangian wave packet is advanced for a small time Δt. The scattering from fluctuations is examined by a Monte Carlo evaluation of the integral part of the wave equation