Fusion energy is the energy source at the center of stars, including our sun. Like most of the universe, stars comprise hydrogen, the simplest and most abundant element in the cosmos, created during the Big Bang. The center of a star is so hot and dense that the immense pressure forces hydrogen atoms together. These atoms are forced together so strongly that they create new atoms entirely—helium atoms—and release a staggering amount of energy. This energy is called fusion energy.
Fusion energy has many potential advantages over other forms of energy production, such as fossil fuels or nuclear fission. Fusion does not produce greenhouse gases that cause climate change. It uses abundant and cheap fuel sources (hydrogen), makes no radioactive waste or long-lived byproducts, has high efficiency and reliability, and can be scaled up to meet global demand. However, achieving fusion on Earth is very challenging, as it requires creating and maintaining exceptionally high temperatures (over 100 million degrees Celsius) and pressures (over 100 billion atmospheres) long enough to initiate and sustain a fusion reaction.
One way to achieve fusion on Earth is to use devices called tokamaks or stellarators, doughnut-shaped chambers containing plasma (a state of matter where electrons are separated from nuclei) under strong magnetic fields. The magnetic fields confine the plasma in a closed loop or ring shape, preventing it from touching the walls or escaping through gaps. Electric currents or microwaves must heat the plasma until it reaches temperatures high enough for fusion between hydrogen isotopes (deuterium and tritium). The fusion reaction releases more energy than it consumes, creating a net gain.
Another way to achieve fusion on Earth is to use devices called inertial confinement lasers (ICLs), which use powerful lasers to compress and heat a tiny pellet of fuel (usually deuterium-tritium) until it reaches temperatures high enough for fusion. The laser beam creates a shock wave that squeezes the pellet into a smaller volume in a fraction of a second. The resulting explosion releases more energy than the laser beam consumed.
Both tokamaks and ICLs face many technical challenges before becoming commercially viable fusion energy sources. Some of these challenges include finding suitable materials that can withstand extreme conditions without melting or breaking down, developing efficient methods for extracting proper heat from the plasma without wasting too much power on heating or cooling systems, ensuring safety and reliability against potential hazards such as plasma instabilities or runaway reactions, reducing costs and environmental impacts associated with construction and operation.
One promising alternative approach to achieve fusion on Earth is field reversed configuration (FRC), which uses devices that confine plasma on closed magnetic field lines without a central penetration. In an FRC device called an electrostatic mirror (ESM), an electric field reverses around an axis perpendicular to an external magnetic field applied along another axis perpendicular to both fields. This creates two opposite regions: one with positive charge density (the mirror region) facing away from an external electric field and one with negative charge density facing towards an external electric field.
The ESM device consists of two concentric rings: one with electrodes attached along its inner edge and one with electrodes attached along its outer edge; both rings have opposite polarity: one positive inside and one negative outside; both rings have an opposite current direction. One current flows clockwise; one current flows counterclockwise; both rings have opposite voltage directions: one voltage applies across them, and one voltage opposes them. When an external magnetic field is applied perpendicular to both rings along their inner edges, this creates two opposing magnetic fields inside each ring: one inside ring has positive magnetic flux density; one inside ring has negative magnetic flux density; both inside rings have an opposite direction: one inside ring points towards ESM axis; one inside ring points away from ESM axis.
When an external electric field is applied across both rings along their outer edges, this creates two opposing electric fields between each ring: one between rings has a positive electric potential difference; one between rings has a negative electric potential difference; both between rings have an opposite direction: one between rings points towards ESM axis; one between rings suggests away from ESM axis. When these two opposing forces act on each other along their inner edges, they create two opposing toroidal currents in each ring: one toroidal current flows clockwise in the mirror region along the inner edge electrode; another toroidal current flows counterclockwise in the mirror region along the outer edge electrode.
We must use field-reversed configuration magnetic fields for our plasmas and maintain the ability to capture electricity directly through electromagnetism propulsion. This means we create a three-dimensional magnetic piston that induces a current by pushing back on the magnetic field holding the dense plasma once fusion occurs; this causes the highest efficiency capture.