Conceptual design of DIII-D experiments to diagnose the lifetime of spin polarized fuel

Nuclear Fushion

article

A.V. Garcia¹  W.W. Heidbrink¹  A.M. Sandorfi² 

[1] Department of Physics and Astronomy, University of California;Physics Division, Thomas Jefferson National Accelerator Facility

关键词: spin polarized fusion;    DIII-D;    charged fusion products;    fusion reactions;   

DOI  :  10.1088/1741-4326/acaf0d

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

In magnetic fusion experiments, the cross sections for the D-T and D-³He fusion reactions are increased by as much as 50% if the fuel remains spin polarized parallel to the magnetic field. The goal of this study is to assess the feasibility of lifetime measurements of spin polarization, in magnetic fusion relevant conditions, on the DIII-D tokamak using relative changes in charged fusion product (CFP) loss measurements that depend upon the differential fusion cross section d σ /dΩ. Relative measurements that capture changes in the escaping CFP pitch, poloidal, and energy distributions are studied in two realistic TRANSP calculated plasma scenarios: (a) vector-polarized ³He and D pellets are injected into a hot hydrogen plasma to produce thermonuclear reactions, and (b) a tensor-polarized deuterium pellet is injected into an L-mode hydrogen background plasma that includes unpolarized ³He neutral beam injection. Ideal CFP signals in both scenarios show substantial pitch sensitivity to polarization for 14.7 MeV proton detection at a poloidal angle of -56^{circ}(on the outer wall in the ion abla Bdirection), and strong sensitivity to polarization for 3.6 MeV alpha flux detection by an array of poloidal detectors. Energy-resolved measurements of 14.7 MeV protons are also sensitive to the degree of polarization for the -56^{circ}port in the beam-plasma scenario. A realistic assessment of CFP signals in the thermonuclear scenario show count rates in the range of 2imes10^4  cps for pitch-resolved proton detection and 2imes10^5  cps for alpha flux measurements. Reduced chi-squared chi^{,2}_mathrm rcalculations show polarization lifetime measurements are feasible for either proton or alpha detection of both enhanced or suppressed polarization for the thermonuclear scenario. Measurements of gamma rays produced in the weak extrm{D} + {}^{3}extrm{He} rightarrow gamma+ {}^5extrm{Li}branch complement the CFP measurements.

【 授权许可】

Unknown