Is Nuclear Fusion Finally Within Reach?

Sep 15 2020 | By Ryan Mandelbaum

The HBT-EP Tokamak at Columbia University.

Fuse two hydrogen atoms, and the result is a massive release of energy akin to the energy that powers the sun and stars. Even better: The process emits only inert helium gas, not greenhouse gases. The challenge: fusion devices must heat their hydrogen plasmas to well over 100 million degrees Celsius—roughly ten times hotter than the temperature of the sun—and keep that plasma controlled and confined.

Dramatic advancements in fusion technology have brought the first tests of sustained fusion energy production within sight, thanks in no small part to the work of applied scientists at Columbia Engineering. Around 2030, an international team of scientists and engineers is scheduled to complete ITER, the world’s largest fusion experiment. When fully operational, the scientific and technical achievements embodied in ITER will provide a critical step toward delivering abundant electricity from fusion energy.

Applied scientists at Columbia are currently developing novel techniques to control the hot plasma that will be confined by ITER’s strong magnets and in similar but smaller devices such as the High Beta Tokamak–Extended Pulse (HBT-EP) experiment in the Columbia Plasma Physics Laboratory.

Imagine a society where we don’t have to worry about the supply of energy or the cost of sustainability.

Michael Mauel
Professor of Applied Physics

A tokamak is a device that confines plasma in a torus surrounded by magnetic field-generating coils, while another current-generating coil runs through its middle. Gerald Navratil, Thomas Alva Edison Professor of Applied Physics, and Michael Mauel, professor of applied physics, use the HBT-EP to investigate causes of instability in plasmas at high pressures, and then apply magnetic control feedback using advanced algorithms and optical sensors to suppress those instabilities. Their advances at HBT-EP and the DIII-D National Fusion Facility in San Diego have already raised the pressure limit at which tokamaks can stably operate and increased their power production capabilities—work that will be incorporated into ITER once it begins to run at higher pressures.

Scientists create magnetic bottles in other configurations as well. One alternative design, the stellarator, relies on twisted magnetic-field-generating coils surrounding the torus to confine the plasma. Early stellarator experiments lost energy quickly and struggled to reach sufficient temperatures. But in the 1970s and 1980s, Allen Boozer, professor of applied physics, developed core mathematics governing magnetic fields and particle behavior in the stellarator, which allowed designers to overcome these problems. Today, Boozer is refining designs to the modern version’s magnetic field-generating coils and waste product-removing diverters. The largest stellarator, the Wendelstein 7-X in Germany, is based in part on his research.

Such experiments could ultimately transform the way we create energy in the United States.

“Imagine a society where we don’t have to worry about the supply of energy or the cost of sustainability,” says Mauel. “We have a lot to do to get there. But the benefit of abundant, clean fusion energy makes the pursuit worthwhile.”