JET Fusion Performance Analysis.pdf

- Purpose: Investigate fusion performance, beam-target neutrons, and synergistic effects in JET high performance pulses.
- Method: Analyze JET's best performing baseline and hybrid pulses, focusing on density, central electron and ion temperatures, and their ratio (Ti(0)/Te(0)).
- Findings:
- Thermal fusion gain increases linearly with normalized plasma pressure (βN) and confinement (Btτ).
- Beam-target (BT) neutrons are harder to predict and depend on central fast ion densities, which decrease with increased density and density peaking.
- Higher central ion temperature and Ti(0)/Te(0) ratio lead to increased total and BT reaction rates, but decrease BT to total neutron ratio.
- NB/RF synergistic effects have negligible impact on total neutron rate due to reduced beam penetration at high density.
- Background: JET's scientific program focuses on preparing for a deuterium-tritium (DT) campaign, with upgrades to the neutral beam (NB) system to deliver up to 34 MW. Two operational scenarios—baseline and hybrid—have been developed for sustained high DT fusion power.
- Previous Work: Earlier studies estimated that 40-60% of DD reactions in high performance pulses and about 50% of total neutrons in DT experiments originate from BT reactions. NB/RF synergistic effects have been shown to impact DD neutrons in previous JET campaigns.