Diagnostic Fusion in Fusion Machines
Fusion plants carry magnetic, optical, neutron, and thermal diagnostics; fusing them reconstructs plasma and machine states no one diagnostic sees.
A diverse diagnostic set
A fusion machine is watched by many diagnostic families, each sensitive to a different physical process and each with its own noise, latency, and survivability. A predictive twin fuses them so their strengths add and their blind spots are covered. The following families are representative of what the Kronos machines will carry.
The families
- Magnetic: pickup coils and flux loops sensing fields and currents, fast and robust, the backbone of equilibrium reconstruction
- Optical and spectroscopic: light emission revealing temperature, density, and impurity content
- Neutron and particle: counts and spectra reporting the fusion reaction rate and its distribution
- Thermal: thermocouples and infrared sensing heat loads on internal surfaces
- Structural and electrical: strain, vibration, and power-supply signals reporting machine health
Why fusion of diagnostics is essential
The most important quantities are hidden. The internal current profile of the Hyperion plasma, its pressure profile, and the true heat flux to plasma-facing surfaces cannot be measured directly. Combining magnetic measurements with pressure and radiation data through a physics model reconstructs them, a technique that treats every diagnostic as a partial constraint on one consistent state.
Cross-checking and fault detection
Because families overlap, fusion also polices sensor health. If the neutron rate implies a fusion power inconsistent with the temperature and density from spectroscopy, one of them is wrong, and the twin flags it rather than silently averaging. This cross-diagnostic consistency is a first line of anomaly detection.
Differences between the machines
The breeder Hyperion, a spherical tokamak, leans heavily on magnetic and neutron diagnostics for its deuterium-tritium plasma. The burner, a deuterium-helium-3 tandem-mirror generator with a 26.49 tesla plug and a low neutron fraction of 5.44 percent, weights its diagnostic fusion toward magnetic, particle, and direct-conversion electrical signals. The twin architecture is shared; the diagnostic weighting is machine-specific. See plasma state reconstruction.