Our Technology

The Basics I: Linear Electrostatic Ion Traps

Just as photons can be trapped in an optical cavity by bouncing light waves between reflecting curved mirrors, charged particles, subject to electromagnetic forces and the laws of charged particle optics, can also be confined indefinitely using electrostatic reflectors. This principle, pioneered at the Weizmann Institute in Israel a decade ago, forms the basis for a radically new means to trap energetic ions in a table-top device.  Ion beam storage otherwise had generally involved, cumbersome, and expensive magnetic storage rings. FPGeneration is taking linear electrostatic ion traps to the next level, with the innovative addition of magnetic fields and electrons.

The Basics II: Inertial Electrostatic Confinement (IEC)

In IEC, invented by Philo Farnsworth and Robert Hirsch at ITT labs in the 1950s, positively charged nuclei – ions – are accelerated into the center of a spherical vacuum chamber by a negatively charged, spherical grid. Daunting temperatures are easily achieved with relatively small high-voltage power supplies – for example the effective temperature of an electron hitting the screen in a cathode ray tube is tens of millions of degrees. IEC was one of the earliest schemes considered to produce  fusion power in the laboratory. However, the key to the success of any fusion reactor is to keep significant numbers of ions close together, for long enough time, and moving sufficiently fast so that enough fusion reactions occur to produce more energy than must be spent in heating the ions up in the first place. In Farnsworth and Hirsch’s machine, too many ions impact the grid before fusing to produce net energy, and not enough mutually repulsive ions can be focused into a spot at the center of the device to make useful amounts of power. IEC research as a means to a source of energy was more or less abandoned in the 1970s, but an interesting revival of the underlying idea occurred with invention of the Polywell, proposed by R.W. Bussard in 1989.

First Steps: Multi-pole Ion beam Experiment (MIX)

By adding a particular type of magnetic field to a quasi-spherical IEC device,  we in effect replace the cathode grid with a shaped electromagnet that also doubles as the accelerating cathode. As a result, a number of improvements over the traditional "fusor" are possible. We are able to dramatically lower the losses of energetic ions that limit the efficiency of traditional designs, increase the amount of recirculating ion current that can be contained, and use the cusped magnetic field to contain a warm trapped plasma, which serves as an indestructible fusion target. With additional electron injection into the core, Gabor lensing can also aid in ion focusing and increase peak densities. More info

Pushing the Boundaries: Multiple Ambipolar Recirculating Ion Beam Experiment (MARBLE)

One of the major obstacles that limits the fusion output in IEC devices is the result of repulsive electrostatic forces arising from the ions themselves. This limits the amount of current that can be injected/contained, and is related to the well-known Child-Langmuir current limit for unneutralized particle beams. In 2010 FPGeneration invented an approach that circumvents such limitations, by overlapping mutliple ion beams at different energies on the same axis. This is a significant breakthrough which has the potential to impact a number of technologies (wherever space charge limitations arise). More info 

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