Avalanche heats desktop fusion plasma above 10 million degrees

Avalanche says its desktop-scale fusion prototype has heated plasma to roughly 11 million degrees Celsius, a threshold that puts the startup in a small club of companies reporting temperatures above 10 million, according to TechCrunch. The company has raised less than $50 million in venture funding to reach the milestone, and it says the result was validated by a plasma physicist at MIT, though the data has not been published in a peer-reviewed journal.

The number is not a promise of electricity anytime soon: TechCrunch notes that no fusion reactor has yet been built that can generate power. But temperature is one of the variables that determine whether a fusion device is doing more than making an impressive laboratory glow. In the fusion world, plasma heat is typically expressed in particle energy (kiloelectron volts) rather than a thermometer reading, and TechCrunch cites Commonwealth Fusion Systems chief executive Bob Mumgaard saying that getting above 1 keV is enough to draw worldwide attention.

Avalanche is trying to turn that attention into a different kind of business plan. Many fusion startups are designing large machines meant to produce dozens or hundreds of megawatts of electricity, with timelines and capital needs that resemble national infrastructure projects. Avalanche is instead betting that smaller hardware can be iterated faster and, if it works, sold into markets that already buy compact power—diesel generators and natural-gas turbines—without waiting for the kind of grid-scale deployment that tends to bring regulators, public financing, and long procurement cycles.

The company’s latest fusion core, a device it calls Jyn, has a core about five inches in diameter, TechCrunch reports. Avalanche says it has updated the device 25 times since the fall of the previous year, a cadence that is easier to sustain when prototypes fit on a desktop rather than inside a purpose-built facility. That speed matters because fusion performance depends not just on heat but also on density and how long the plasma can be held together; each design change is an attempt to push more than one of those constraints at once.

The gap between a hot plasma and a working power plant is where fusion companies usually run out of patience or money. Avalanche’s claim, if it holds up under broader scrutiny, suggests the early-stage milestones may be achievable with less capital than the sector’s dominant approach assumes—while leaving the hardest accounting question unanswered: whether the device can ever produce more energy than it consumes.

For now, the most concrete output from Avalanche’s reactor is a temperature estimate and a prototype that can be measured in inches.