Neutron emission from TFTR supershots

Abstract

Empirical scaling relations are deduced describing the neutron emission from TFTR supershots using a database that includes all of the supershot plasmas (525) from the 1990 campaign. A physics based scaling for the neutron emission is derived from the dependence of the central plasma parameters on the machine settings and the energy confinement time. This scaling has been used to project the fusion rate for equivalent DT plasmas in TFTR, and to explore the machine operation space that optimizes the fusion rate. Increases in neutron emission are possible by either increasing the toroidal magnetic field or further improving the limiter conditioning

Fusion nuclear science facilities and pilot plants based on the spherical tokamak

“…The fast-ion and thermal stored energies are then used to compute the total stored energy, β N , and β T values. Fusion powers and neutron rates are computed from scalings for thermonuclear and beam-target [116] similar in form to the ITER scaling described in [119] but consistent with lowaspect-ratio equilibrium calculations [17,20,27]. The total non-inductive current for a given scenario is then calculated from the sum of the bootstrap and NBI currents.…”

Alpha particle physics experiments in the Tokamak Fusion Test Reactor

“…An empirical study of T e (0) scaling in 380 campaign [115] were evaluated 0.7 s into the neutral beam heating pulse, which was late enough for the alpha particle population to build up, but early enough to avoid "rollover" of plasma performance or turn-off of the heating beams.…”

Evaluation of the operational parameters for NBI-driven fusion in low-gain tokamaks with two-component plasma

“…For the injection heating regimes with Q ≈ 1 the optimal values of injection energies are 160 keV (deuterons) and 240 keV (tritium nuclei). In our analysis, it was assumed that the ratio of fast particles is as high as 50% (n i,f ≈ n i,th ) that is comparable with n i,f ≈ 0.5n i,th in TFTR experiments [20].…”

“…These values seem too high. For example, n i,f /n i,th ≈ 0.5 in TFTR experiments [20]. If injection provides 50% of total particle source (C inj = 2) the ratio n i,f /n i,th ≈ 0.3-1.…”

“…Design of TFTR takes into account the possibility to increase the plasma reactivity by neutral beam injection due to beam-thermal and beam-beam reactions [13]. Fast ion fraction n i,f /n i,th ≈ 0.5 was achieved [20]. The value of plasma gain Q reached 0.27 in TFTR, which was less than some of the more optimistic projections performed during the design phase [15].…”