Nuclear Fusion with Christina Migliore

NOTE: This episode was recorded in early 2022, before the invasion of Ukraine by Russia and their attack on the Chernobyl nuclear facility, which we discuss.

What’s up with nuclear fusion? Dr. Charles Liu dives into the heated subject with the help of MIT Nuclear Physicist Christina Migliore and co-host Allen Liu.

We start with today’s joyfully cool cosmic thing: the JET, or Joint European Torus. JET is a “giant metal donut” in the UK engaged in plasma physics and nuclear fusion. You’ll learn about magnetic containment devices known as “tokamaks,” the most common form of experimental devices with which to create nuclear fusion. Find out about plasma, the fourth state of matter, and how difficult it is to work with.

Speaking of hot balls of plasma, aka stars, Caroline from the Pingree School asks, “What is fusion and why does it occur in stars?” Find out about different forms of fusion, their sources, and their outputs. Learn about the strongest laser in the world, the National Ignition Facility (NIF) at Lawrence Livermore Labs, which is on the cutting edge of generating energy from fusion.

Josh, another student at the Pingree School, wants to know how nuclear fusion would be affected by strong gravitational forces. We explore why stars can use strong gravity to sustain their fusion, but we can’t do that here on Earth…yet.

We also delve into the two “hottest” topics in the field of nuclear fusion research. First, Christina tells us about the engineering aspect of building high magnetic field devices, including high temperature superconductors. Next, Christina explains her work studying wall interactions with plasma to minimize the creation of hotspots that generate impurities. (Geek Warning: Chuck and Christina nerd out a bit a wavelengths, energy outputs, rectification, cold plasma, boundary conditions, Maxwell’s Equations, and more!)

Pseudoscience rears its ugly head when Chuck and Christina dive into the concept of cold fusion, made famous by Iron Man’s ARC Reactor in the MCU. Before the episode ends, we unpack the difference between nuclear fusion and nuclear fission, the value of each when pursued responsibly, and issues surrounding history, safety and aging infrastructure. And we touch on Chernobyl, the design flaws that led to the situation, and the bureaucratic concerns that pushed it over the edge. Finally, you’ll hear how MIT is developing a new device called SPARC that will create a very strong magnetic field that could eventually let us put fusion generators on the energy grid.

Credits for Images Used in this Episode:

- Interior of the JET tokamak (2) – Credit: EUROfusion

- National Ignition Facility (NIF) preamplifiers – Credit: Damien Jemison/LLNL

- Interior of the Alcator C-Mod tokamak at MIT – Credit: Bob Mumgaard/Plasma Science and Fusion Center

- The Sun – Credit: NASA/SDO/AIA

- Chernobyl Unit 4 reactor after April 26, 1986. Credit: International Atomic Energy Association (via Creative Commons BY-SA 2.0)

- MIT SPARC – Credit: CAD rendering by T. Henderson, CFS/MIT-PSFC