Project 04 · Written with Ryan Kang

Nuclear Fusion, A Quantitative Survey

A research paper on fusion theory, the two reactor engineering approaches that actually get used, and the newer work pushing net energy gain closer to reality, like AI based instability prediction and liquid metal wall materials.

The Sun imaged by NASA's Solar Dynamics Observatory, the reference fusion reactor — The Sun, the only fusion reactor with a proven track record.
NASA/SDO (AIA), public domain

Sources cited: 34
Confinement methods covered: 2
Target D-T fusion temperature: 150M K
AI tearing-mode prediction lead: 300ms

Plasma physicsNuclear fusionResearch writingQuantitative modeling

Who: I wrote this with Ryan Kang and we split it evenly across the theory and the engineering methods.
Why: It is not related to my other projects, and it is here as a writing and research sample instead of a propulsion piece.
How: The paper works through the real derivations instead of only describing the concepts, and it is upfront about where it stops.
Open: One derivation in the theory section was past what we could do from first principles, and we say that directly in the paper instead of hand waving past it.

Two ways to satisfy Lawson's Criterion

The criterion needs the product of ion density and confinement time to clear a threshold, and there are two opposite ways to get there.

Magnetic confinement

Hold it for a long time, at low pressure

Diagram of toroidal and poloidal magnetic fields in a tokamak

U.S. Dept. of Energy, public domain

Inertial confinement

Hold it for nanoseconds, at extreme pressure

B. D. Esham / U.S. Government, public domain

Theory

We derive the energy released by hydrogen to helium fusion straight from the mass defect and E=mc², then work through why fusion is hard in the first place.

Engineering methods

This covers the two approaches real reactors use.

Modern advancements

Tearing instabilities and magnetic islands, including how Princeton's AI based predictive control forecasts a tearing instability up to 300ms before it happens instead of reacting after the fact.

Looking to the future

An honest look at what is still unsolved.

Preview of a page from the fusion research paper

Read the paper

22 pages and 34 cited sources, with worked derivations for the mass defect, the Coulomb barrier and Lawson's Criterion.

Open full PDF

Image credits: solar image NASA/SDO (AIA), tokamak field diagram U.S. Department of Energy, inertial confinement diagram Benjamin D. Esham after a U.S. Government original. All of them are public domain.