Mark Megahan
Zap Energy came up with a truly radical new fusion reactor design. One that generates the intensely strong magnetic fields needed to contain hundred million degree plasma without using any magnets.
Fusion gets freaky
If all goes well, Zap Energy’s FuZE-Q demonstration reactor will be online by the summer of 2023. Until now, fusion has been generated in devices called “tokamaks” and “stellarators” which use powerful and complex magnetic coils to “contain the high-temperature plasma in which atomic nuclei fuse and release energy.”
This new breakthrough is a totally different concept than the idea Michael Zarnstorff came up with to replace the coils with more efficient neodymium–boron permanent magnets, which we reported on back in November.
Despite all the advances in superconducting magnets, traditional magnetic-confinement fusion hasn’t come to fruition yet. A functioning carbon-free power plant seems years away.
The design that Seattle-based Zap Energy calls their FuZE-Q reactor, “bypasses the need for costly and complex magnetic coils” by sending “pulses of electric current along a column of highly conductive plasma.”
Doing it that way spontaneously creates “a magnetic field that simultaneously confines, compresses, and heats the ionized gas.” Fusion experts call that a “Z-pinch approach” because “the current pinches the plasma along the third, or Z, axis of a three-dimensional grid.”
Putting it simply, it could generate electricity “in a device that’s simpler, smaller, and cheaper than the massive tokamaks or laser-fusion machines under development today.”
Plagued by instability
Z-pinched plasma designs have been around for years. The problem with them is that the style of fusion reactors has “historically been plagued by instabilities.”
Without a custom made magnetic field to provide “a perfectly uniform squeeze,” the plasma itself “wrinkles and kinks and falls apart within tens of nanoseconds.” That won’t keep the lab lights on. Far “too short to produce useful amounts of electricity.”
Zap Energy patented what they like to call “sheared-flow stabilization” for their fusion reactor. It “tames these instabilities by varying the flow of plasma along the column.” The design itself “sheathes the plasma near the column’s central axis with faster-flowing plasma.” They explain it works like “a steady stream of cars traveling in the center lane of a highway, unable to change lanes because heavy traffic is whizzing by on both sides.”
Test runs indicate “the new machine, budgeted to cost about $4 million, will dial up the strength of the pulses from 500 kiloamperes to more than 650 kA—the approximate threshold at which Levitt and his team believe they can demonstrate breakeven.”
The physicists believe that arrangement will keep the plasma “corralled and compressed longer than previous Z-pinch configurations could.” If not, it will explode violently. “We think our reactor is the least expensive, most compact, most scalable solution.” Also, the one with the “shortest path to commercially viable fusion power.”
They’re keeping their fingers crossed that they will hit the break-even point where “the energy released by the fusing atoms is equal to the energy required to create the conditions for fusion” by mid-2023. They hope to have it producing power by 2026. They know that’s an optimistic target but “Zap’s ascent of a forbiddingly steep technology curve has been swift and impressive.”
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