Fusão Nuclear Pulsada: Por que a Helion pode vencer o ITER

The Hook: The Steam Turbine Bottleneck

In the south of France, humanity is building ITER, a $25 billion cathedral of science. It is designed to be the first fusion reactor to produce more energy than it consumes. But there is a hidden problem: highly inefficient plumbing.

Even if ITER works perfectly, it is essentially a giant tea kettle. The neutrons from the fusion reaction heat up the walls, which heat up water into steam, which spins a turbine. This “Thermal Cycle” is stuck in the 19th century.

• Efficiency Cap: Steam turbines are limited by the Carnot limit (roughly 35-40%). You lose 60% of your hard-earned fusion energy as waste heat.
• Scale: You need massive cooling towers, heat exchangers, and high-pressure steam pipes. This makes the plant size—and cost—enormous.

Helion Energy is betting on a different physics entirely. They don’t want to boil water. They want to generate electricity directly from the plasma, using the same laws of physics that power your electric toothbrush.

The Physics Deep Dive: Field Reversed Configuration (FRC)

To understand Helion, you have to forget the “Donut” (Tokamak) shape of ITER. Helion uses a Field Reversed Configuration (FRC).

The “Smoke Ring” of Plasma

In a Tokamak (like ITER), the magnetic fields that contain the plasma are generated largely by external superconducting coils. This makes the device complex and static. In an FRC, the plasma generates its own magnetic field as it spins.

• Toroidal Current: The plasma current flows in a ring (like a smoke ring).
• Closed Field Lines: This current creates a magnetic field that wraps around the plasma itself, effectively “bottling” it without needing a central pole.
• High Beta: FRCs have a very high “Beta” (ratio of plasma pressure to magnetic pressure). This means they are incredibly efficient at using magnetic fields, requiring less power to contain more plasma.

The Pulsed Cycle: A Fusion Diesel Engine

Helion’s machine, “Polaris,” works less like a continuous furnace and more like a four-stroke diesel engine:

1. Direct Injection (Intake): Magnets inject deuterium and helium-3 gas into the formation sections at each end of the machine.
2. Formation (Compression): Field coils pulse, creating two FRC plasmoids—one at each end.
3. Acceleration (Combustion): sequential magnetic coils fire like a railgun, accelerating these two plasmoids towards the center of the machine at 1 million mph (400 km/s).
4. Collision (Power): They smash together in the central chamber. The kinetic energy of the collision, combined with a massive magnetic squeeze (compression), heats the plasma to 100 million degrees C. FUSION HAPPENS.

Direct Energy Capture: Faraday’s Law

This is the “magic” trick. In a traditional reactor, the energy comes out as high-speed neutrons (which you catch with water). In Helion’s reaction, the energy comes out mostly as charged particles (Alpha particles and Protons).

As the fusion explosion happens, the plasma ball expands violently. It pushes back against the magnetic field that confined it.

$\mathcal{E} = -N \frac{d\Phi_B}{dt}$

Recall Faraday’s Law of Induction (or Lenz’s Law): Changing a magnetic flux ($\Phi_B$) induces a voltage ($\mathcal{E}$) in a coil.

• Compression: We put electricity in to squeeze the magnets (doing work on the plasma).
• Fusion: The fusion reaction adds massive thermal energy, increasing the plasma pressure.
• Expansion: The plasma pushes back, expanding the magnetic field lines.
• Recovery: This moving magnetic field induces a current back into the coils.

It is exactly like regenerative braking in an electric car. The kinetic energy of the expanding plasma is converted directly back into electricity in the wire. Helion claims this “Direct Energy Recovery” can capture 95% of the input energy, plus the new fusion energy, directly as electricity. No steam. No turbines. No heat loss.

The Fusion Fuel Problem: Why D-He3?

You can’t do direct energy recovery with just any fuel.

• D-T (Deuterium-Tritium): The fuel used by ITER. It releases 80% of its energy as Neutrons. Neutrons have no charge; they fly right through magnetic fields. You cannot catch them with induction. You must use a blanket to catch them as heat (Thermal Cycle).
• D-He3 (Deuterium-Helium-3): The fuel used by Helion. It releases most of its energy as Protons (charged). Protons are trapped by magnetic fields. PROTONS push the field.

This is why Helion is obsessed with Helium-3. It enables the physics of direct capture. The catch? Helium-3 is rare on Earth. Helion plans to make their own Helium-3 by fusing Deuterium-Deuterium in a side reaction, essentially breeding their own fuel.

Zap Energy: The Shear Flow Z-Pinch

Helion isn’t the only one skipping the donut. Zap Energy is using a Z-Pinch.

A Z-Pinch is the simplest way to squeeze plasma: You shoot a lightning bolt of current through a column of gas. The magnetic field generated by the current squeezes the gas (Lorentz Force).

• The Problem: Z-Pinches are notoriously unstable. They develop “sausage” and “kink” instabilities within nanoseconds, tearing the plasma apart before fusion happens.
• The Solution: Zap uses Sheared Flow Stabilization. By forcing the outer layers of the plasma column to flow faster than the inner layers (velocity shear), they smooth out the instabilities.

Think of it like a river: A stagnant pool gets stagnant and chaotic. A fast-flowing river stays in its channel. Like Helion, Zap is a compact, pulsed system that could be mass-produced in a factory, unlike the bespoke construction project of ITER.

Comparison: The Tortoise vs. The Hares

Feature	ITER (The Standard)	Helion (The Rebel)	Zap Energy (The Dark Horse)
Physics	Tokamak (Steady State)	Magnetic Inertial Fusion (Pulsed)	Sheared Flow Z-Pinch
Energy Capture	Thermal (Steam Turbine)	Direct Induction	Thermal (Liquid Lead Blanket)
Fuel	Deuterium-Tritium	Deuterium-Helium-3	Deuterium-Tritium
Scale	Small City ($25B+)	Shipping Container	Garage Size
Efficiency Limit	~40% (Carnot)	>85% (Theoretical)	~40% (Carnot)
Neutron Damage	High (Blanket Degradation)	Low (Aneutronic)	High (Liquid Wall Protection)

Forward-Looking Analysis: The “Net Electricity” Trap

The media often confuses $Q_{plasma}$ (Physics Gain) with $Q_{engineering}$ (Wall Plug Gain).

• ITER aims for $Q_{plasma} > 10$. It proves the science, but will never put a watt on the grid. It consumes hundreds of megawatts to run the cryogenics.
• Helion aims for Net Electricity. Because they skip the steam cycle, their threshold for commercial viability is actually lower in some ways, but the physics (D-He3 ignition) is harder because it requires much higher temperatures (100M+ degrees vs 15M degrees for D-T).

If Helion’s “Polaris” machine works in 2025/2026, it renders the Thermal Cycle obsolete for fusion. We might skip the “Steam Age” of nuclear fusion entirely and jump straight to the “Electric Age.”

The difference is history. ITER is building a science experiment. Helion is building a product.