Chatwood Labs Publishes Pre-Print on Phase-Aligned Fuel Injection in Reduced Burn Propagation Model
Pre-print study examines phase-dependent fuelling effects in a reduced toroidal model, highlighting timing as a potential control variable in burn propagation dynamics.
Chatwood Labs has published a new pre-print examining the role of fuel injection timing in systems where burn propagates as a moving structure.
The study investigates whether the temporal phase of fuelling relative to a propagating burn crest can influence system behaviour, even when total fuel input remains unchanged. While fuelling in magnetically confined plasmas is typically considered in terms of rate, location, and penetration depth, the timing of fuelling relative to evolving burn structures has received comparatively little attention.
To explore this, a reduced one-dimensional toroidal model was developed in which crest propagation is represented through prescribed advection together with simplified source, transport, thermalisation, and exhaust closures. The model is presented as a conceptual mechanism study rather than a predictive plasma calculation.
Across a full lag scan, the results show a clear phase dependence. Injection close to the burn crest produces the strongest immediate response but is short-lived. By contrast, delayed injection into the wake region sustains propagation for significantly longer. Asynchronous fuelling performs similarly to the no-injection baseline despite receiving the same scheduled fuel input per orbit.
Sensitivity testing, grid convergence analysis, and Monte Carlo parameter variation were used to assess robustness. Across these tests, the phase-dependent propagation behaviour and extended wake-aligned regime persist, with termination criteria affecting the detected collapse boundary rather than the existence of the regime itself.
The results indicate that structured fuelling may influence propagation dynamics in this reduced system even when total fuel input is unchanged. This suggests that fuel injection timing may form part of the control architecture in systems exhibiting propagating burn behaviour, rather than acting solely as a fuel delivery parameter.
This work is part of the broader Chatwood Labs simulation programme, focused on reduced-order modelling, higher-dimensional validation, and the staged development of control-oriented fusion concepts.