Alpha-particle losses during slowing-down in an open-field-line fusion plasma

Abstract

Alpha-particle losses due to pitch-angle scattering into the loss cone of an open-field-line configuration are investigated. Specifically, the particle loss and the corresponding energy loss are given as explicit functions of energy during slowing-down. It is found that the alpha-particle energy loss due to pitch-angle scattering for a pure DT-plasma is of the order of 5–10%, in contrast to the 35–40% obtained in a recent paper

Kinetic analysis of nuclear and Coulomb scattering in high-temperature tandem mirror plasmas

“…Rensink et al [4] and others [5][6][7] have calculated fusion product energy deposition, and energy and particle end-loss rates in mirrors due to Coulomb scattering only. All results are in general agreement with those of Rensink et al, who found that in a d-t reactor plasma about 10% of the alpha energy and 25% of the particles are lost by this mechanism.…”

“…b -1 dv' (6) In these variables, changed from speed to energy, with no spatial dependence and azimuthal symmetry in velocity space, the large-angle scattering collision operator (Eq. ( 7)) becomes…”

“…The primary loss mechanism, for charged fusion products during slowing down and for ions resulting from neutral-beam injection in the plug, is scattering into the loss cone in velocity space. All previous work [3][4][5][6][7] on these problems has considered only Coulomb scattering. In this paper we consider the influence of nuclear elastic scattering on end loss and energy deposition rates in tandem mirrors.…”

Distribution function and diffusion of α-particles in DT fusion plasma

“…Since the energy of a-particles produced by DT reaction is much greater than the plasma temperature and the a-particle deceleration path is in most cases greater than the plasma dimensions, the distribution function of non-thermal a-particles is of particular interest. This non-Maxwellian distribution function has been calculated analytically and numerically by many authors (Nocentini, Tessarotto & Engelmann 1975;Kolesnichenko 1975Kolesnichenko , 1980Corman et al 1975;Tsuji et al 1976;Saito et al 1977;Ivanov & Shvetz 1980;Lisak et al 1982;Anderson et al 1982).…”

“…Solution (8) may easily be generalized for anisotropic distributions by means of expansion in spherical functions which are eigenfunctions of the operator (6). This may be necessary, for example, when non-thermal a-particle losses are angle-dependent (Anderson et al 1982;Lisak et al 1982).…”