The dream of harvesting usable energy from nuclear fusion lives on.
For decades, scientists have labored to create chambers in which heat hotter than the Sun’s surface, and crushing pressures, would melt hydrogen atoms together, releasing vast quantities of clean energy that could be captured and harnessed to power the world.
The test chambers, usually called tokamaks, are lined with tungsten, carbon, and other heat-resistant materials, while almost unimaginably powerful magnetic fields crush together atoms in the center of the chambers, far enough from the walls that the massive heat unleashed by the reactions dissipates before it can melt any equipment.
So far, “success” has been defined by creating the target temperatures and pressures and maintaining them for a few minutes. Sometimes a fusion reaction occurs.
That’s been enough to encourage fusion’s faithful to labor onward.
Early this month, China’s Experimental Advanced Superconducting Tokamak fusion reactor reportedly created a plasma that maintained a temperature of 70 million degrees°C, about 126 million°F, for 1,056 seconds, or more than 17 minutes—the first time a fusion reactor has kept up its heat for more than 1,000 seconds.
The Sun’s temperatures are estimated to be 27 million°F at the core and about 10 million at the surface.
However, China’s reactor didn’t create an actual fusion reaction. It only demonstrated its ability to not melt or vaporize itself over that period.
In Everett, Wash., the U.S. startup Helion has raised billions so far by promising to demonstrate a workable fusion technology within two years.
Helion has built a reactor that has completed more than 10,000 tests, most lasting less than a millisecond, and, earlier this year, created an internal temperature above 100 million°F, considered the threshold heat level for sparking a self-sustaining, commercial fusion reaction in a chamber.
Helion’s drawn attention because of its downstream concept: instead of using fusion’s heat to make steam and drive turbines, Helion’s design uses it to alter the reactor’s internal magnetic field, creating electromagnetic energy that directly sustains an electric current.
The technology operates at 95 percent efficiency, Helion says.
That sunny picture recently pulled in another $500 million in backing from investment heavyweights including Sam Altman, CEO of Open AI and now Helion’s executive chairman; PayPal co-founder Peter Thiel; Jeff Skoll, former eBay president; and Facebook co-founder Dustin Moskovitz.
Last July, Helion broke ground for an expanded test facility. 
TRENDPOST: As we noted in “Hot Fusion Creeps Closer to Viability” (24 Aug 2021), hot fusion is a hothouse of scientific and engineering creativity that, so far, has shown no ability to deliver the technology needed to make a commercially viable power plant that can continuously and indefinitely contain temperatures of millions of degrees without degrading.
Still, various “breakthroughs” continue to draw money from governments, private companies, and financial adventurers including Jeff Bezos and Bill Gates, as we reported in “New Fusion Energy Method Revives Advocates’ Hopes (2 Mar 2021).
A commercial hot fusion plant may be practical—someday.  For now, claims of breakthroughs can’t be judged credible until they’re scaled and tested in the real world.
By that measure, hot fusion is unlikely to be ready to contribute meaningfully to the world’s energy mix before 2040, given not only the needed technological and engineering breakthroughs, but also the regulatory and financing hurdles fusioneers will have to work their way through.

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