Pyroelectric fusion

Pyroelectric fusion is a process of nuclear fusion induced by an electric field from pyroelectric crystals. The basic principle is that the pyroelectric effect is used to generate a strong electric field (gigavolts per metre), by heating the crystal from −30°C to +45°C in a few minutes. The strong field is used to accelerate a beam of the chamber's deuterium atoms from a needle-thin tungsten probe tip mounted on a copper disk into a solid target containing deuterium. Some of the deuterium atoms fuse, producing helium and neutrons. Like muon-catalyzed fusion, the process does not appear to be able to generate net power, but may have other uses.

A UCLA team, headed by Brian Naranjo, has observed the nuclear fusion of deuterium nuclei in a tabletop device in April 2005. The device uses a lithium tantalate (LiTaO3) pyroelectric crystal to ionize deuterium atoms and accelerate the ions towards a stationary erbium dideuteride (ErD2) target. Fusion of two deuterium nuclei results in the emission of helium-4 nuclei (alpha particles), about 1000 2.45 MeV neutrons per second, and gamma rays. The team anticipates applications of the device as a tabletop neutron generator, or in "microthrusters" for space propulsion. It is possible that there may be applications related to nuclear weapons, although this possibility is not discussed in the research paper.

A team at Rensselaer Polytechnic Institute, led by Jeffrey Geuther, has confirmed and improved upon these findings, with a device using two pyroelectric crystals and capable of operating at non-cryogenic temperatures.

Nuclear D-D fusion driven by the pyroelectric effect was proposed by Naranjo and Putterman in 2002. It was also discussed by Brownridge and Shafroth in 2004. The possibility of neutron production (by D-D fusion) was first proposed in a conference paper by Geuther and Danon in 2004 and later in a publications discussing electron and ion acceleration by pyroelectric crystals. The key ingredient of using a tungsten needle to produce sufficient ion beam current was first proposed and demonstrated in the 2005 Nature paper.

This development is not related to earlier claims of tabletop fusion having been observed during sonoluminescence (bubble fusion). In fact, the leader of the team behind this development was one of the main critics of these earlier prospective fusion claims.

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Sources

  • James D. Brownridge and Stephen M. Shafroth, [1], 1 May 2004
  • Jeffrey A. Geuther, Yaron Danon, “Pyroelectric Electron Acceleration: Improvements and Future Applications”, ANS Winter Meeting Washington, D.C, November 14 – 18, 2004.
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External links