Project 03 — Co-authored with Ryan Kang

Nuclear Fusion — A Quantitative Survey

A research paper covering fusion theory, the two dominant reactor engineering approaches, and the modern advancements — AI-based instability prediction, liquid-metal wall materials — pushing net energy gain closer to reality.

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

Written with Ryan Kang, split evenly across theory and engineering methods. It's an unrelated topic to my main projects — included here as a writing and research sample rather than a propulsion-adjacent piece. The paper works through real derivations rather than just describing concepts, and is upfront about its own limits: one derivation in the theory section was judged too advanced to complete from first principles, and the paper says so directly instead of hand-waving past it.

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Two ways to satisfy Lawson's Criterion

The criterion requires the product of ion density and confinement time to clear a threshold — which admits two opposite engineering strategies.

Magnetic confinement

Hold it for a long time, at low pressure

A tokamak's toroidal and poloidal fields combine into a helical field that keeps plasma off the walls. Reactions can be sustained for minutes.

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

High-powered lasers implode a fuel pellet so fast the nuclei fuse before they can move apart — the shell's own inertia does the confining.

Diagram of the stages of inertial confinement fusion

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

Theory

Derives the energy released by hydrogen-to-helium fusion directly from the mass defect and E=mc², then works through why fusion is hard: the Coulomb barrier, and how the Sun gets around it with pressure and quantum tunneling. On Earth, that means picking the right fuel (deuterium-tritium, via fusion cross-sections) and hitting the temperature and confinement time Lawson's Criterion demands.

Engineering methods

Covers the two dominant approaches in real reactors: magnetic confinement (tokamak geometry, gyrocenter/particle motion, and the three heating methods used in ITER) and laser inertial confinement (the Shiva/Nova systems at Lawrence Livermore). Each method is tied back to which side of Lawson's Criterion it's solving for — long confinement at low pressure, or extreme pressure for nanoseconds.

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, versus traditional reactive monitoring — plus liquid lithium wall coatings as an alternative to solid tungsten/beryllium liners.

Looking to the future

An honest accounting of what's still unsolved: reactors are barely past net energy gain, tritium fuel isn't naturally abundant, and funding is currently being cut — read as a real engineering and economics problem, not just a physics one.

Preview of a page from the fusion research paper

Read the paper

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

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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 in the public domain.