Many companies in the U.S. and abroad are researching and developing small nuclear fusion systems. Lawrenceville Plasma Physics (LPPFusion or LPPF) located in Middlesex, N.J. is one such company. Their missions statement says “LPPFusion’s mission is to provide environmentally safe, clean, cheap and unlimited energy for everyone through the development of Focus Fusion technology, based on the Dense Plasma Focus device and hydrogen-boron fuel.”
LPPF began with a small NASA grant to explore fusion propulsion in 1994. In 2001, an LPPF team demonstrated temperatures above one billion degrees Centigrade at Texas A & M University funded by a grant from the Jet Propulsion Laboratory. In 2003, LPPF incorporated as Lawrenceville Plasma Physics. In 2008, LPPF collected one million two hundred thousand dollars from investors and started on Phase I construction. In 2009, LPPF received a patent for some of their technology and set up shop in a laboratory in Middlesex. For the next ten years, LPPF continued raising funds, publishing papers and constructing their first prototype.
The LPPF approach to nuclear fusion utilizes something called a “dense plasma focus” (DPF) device. The DPF is constructed from two cylindrical electrodes with one inside the other. The outer electrode measures about seven inches in diameter and about twelve inches long. The electrodes are placed in a vacuum chamber. A low-pressure gas fills the cylindrical space between the electrodes.
A capacitor bank is used to induce a huge pulse of electricity between the electrodes. A powerful current flows through the gas from the outer to the inner electrode for a few millionths of a second. The gas is heated by the current and an intense magnetic field in generated by the current. The current is influenced by its own magnetic fields and forms a thin sheath of tiny filaments. These filaments are like little tornadoes of ionized gas or plasma.
The sheath of plasma is directed to one end of the inner electrode. Here, the magnetic fields crush the plasma into a plasmoid which is a tiny dense ball of plasma that is only a few thousands of an inch across. The magnetic fields generated by the original pulse quickly collapse. This induces an electrical field which triggers the flow of a beam of electrons to move in one direction while a beam of charged atoms or ion moves in the other direction. The beam of electrons heats the plasmoid to extremely high temperatures of billions of degrees Centigrade. The plasmoid only exists for a few billionths of a second.
The collision of the electrons with the plasmoid generates x-rays. If an x-ray source is the goal, the size and shape of the electrodes and the pressure of the gas can be optimized to generate the most x-rays. If x-rays are not desirable, the parameters of the devices can be adjusted to reduce their generation.
If a fusion reactor for energy generation is the goal, then energy can be transferred from the electron beam to the ions via the magnetic field. Collisions of the ions result in fusion reactions which increase the energy of the plasmoid beyond the energy that was originally applied. The ion beam is sent into a device called a decelerator that slows down the ions. This generates electricity. Some of the electricity is recirculated to keep the system going and the rest is available as electric power.
This approach to fusion is fueled with hydrogen and boron both of which are widely available. There are no pollutants or radioactive waste generated by the DPF. There is no buildup of long-term radioactivity in the device. A small number of low-energy neutrons are emitted but this can be dealt with by a few inches of shielding.
These focus fusion generators will be inexpensive to construct. Because the fusion energy is converted directly to electricity, there is no need for the expensive and complex steam turbine systems that are used by most nuclear power plants today. It is estimated energy generated by focus fusion will cost one tenth of current electricity costs. Focus fusion reactors can also be so small they would fit in to a garage. Such a generator would provide about five megawatts of power which is sufficient to power five thousand homes.