Project Blixt’s Z-Pinch Failure

A Quick Primer on Z-Pinch Fusion

The Z-pinch is one of the oldest concepts in fusion energy, with research dating back decades. It works by sending a strong electric current through a plasma to generate a magnetic field that compresses (“pinches”) the plasma to fusion conditions​.

The allure of Z-pinch is its simplicity: it requires no massive superconducting magnets or giant laser banks, as the plasma is confined by the magnetic field of its own current. The challenge, however, is plasma instability. Virtually all Z-pinch attempts have failed because the plasma becomes violently unstable in microseconds, before meaningful fusion occurs.  

Still, the promise of a simpler path to fusion energy has inspired modern startups to revisit the concept with fresh ideas and new technology.

Project Blixt

Project Blixt was a low-profile initiative within Google X, the company’s 'Moonshot Factory.' With a lean team and modest budget, it sought to revisit an old experimental setup: the “frozen fiber” Z-pinch.

Blixt’s team, led by Matthew Forkin, partnered with veteran researchers from the U.S. Naval Research Lab to fire massive current pulses through a frozen hydrogen wire​. The hypothesis was that the solid hydrogen core might hold the plasma stable, recreating the mysterious longer-lived pinches seen in 1980s tests. 

By early 2025, Project Blixt reached its conclusion, and it wasn’t the breakthrough its team hoped for. Over roughly a year of experiments, Blixt fired 175 high-current shots and gathered extensive diagnostic data. The results were clear: despite a brief initial stabilizing effect from the solid fuel core, the plasma still became unstable almost immediately at microscales​.

The team discovered that the earlier 1980s “anomalous stability” observations were likely inaccurate – the old diagnostics simply couldn’t see the plasma wobbling and breaking apart in the first microseconds. Modern cameras and sensors used by Blixt caught the telltale distortions that proved the Z-pinch still self-destructs too quickly. In short, Blixt confirmed the long-standing scientific concern: an unstabilized Z-pinch, even with a novel frozen fuel, cannot confine plasma long enough for net energy gain.

With that answer in hand, Alphabet’s X decided to wind down Blixt rather than pour more resources into a dead-end. Much to their credit, Blixt’s team is choosing to openly share their findings (and will even display the technology in a public exhibit) rather than quietly shelve the project.

Implications for Fusion Startups

Blixt’s conclusion has two major implications for fusion startups.

First, it effectively closes the door on this particular Z-pinch approach. While it doesn’t condemn all Z-pinch concepts, it provides a well-documented disqualification of one proposed stabilization mechanism. For technical teams, it narrows the field of viable approaches.

Second, the failure reframes the narrative around remaining Z-pinch efforts—particularly Zap Energy, now the only high-profile startup left pursuing the approach. Zap’s strategy diverges significantly from Blixt’s. Rather than relying on passive stability from fuel configuration, Zap actively suppresses instabilities via sheared-flow stabilization, introducing velocity gradients across the plasma column to damp instabilities.

In that context, Blixt’s results arguably reinforce Zap Energy’s approach. It confirms that an unstabilized Z-pinch is untenable, which is exactly why Zap’s shear-flow stabilization is needed. That clarity could strengthen Zap’s narrative as it engages partners, investors, and regulators.

Key Takeaway

In broader private fusion investment circles, Blixt’s outcome is a reminder that fusion startups carry deep technical risk. We’ve seen a surge of funding into fusion companies in recent years, driven by optimism after milestones like the NIF laser ignition success and advances in magnet technology. Blixt’s story injects a dose of realism—not every well-funded experiment will succeed, and no amount of capital or talent can override the constraints of plasma physics.