Thirteen Facts About Nuclear Fusion


Left, from Wikipedia, this photo is an “[I]nternal view of the JET tokamak superimposed with an image of a plasma taken with a visible spectrum video camera.”

(1) Stars are hot stuff. Nuclear fusion occurs naturally in stars and happens when like-charged atomic nuclei join together to form a heavier nuclei.

(2) He’s not heavy, he’s my lower mass nuclei. Nuclear fusion can release or absorb energy relative to whether the nuclei have a mass lower than iron. If the nuclei have a mass lower than iron, the process releases energy, but if heavier than iron the process will absorb energy.

(3) The cycle of nuclear fusion in stars was worked out by Hans Bethe in the 1930s. In 1932 Mark Oliphant observed the fusion of hydrogen isotopes (light nuclei).

(4) As part of the Manhattan Project that created the nuclear bomb (which uses fission not fusion), Hungarian physicist Edward Teller pushed to create the “Super,” a bomb designed to use the force of a fission bomb detonation to ignite a fusion reaction in deuterium and tritium. “Super” seems kind of an understatement, ya think?

(5) The Joint European Torus (JET) is the largest nuclear fusion reactor ever built. It is located in the UK and experiments first began there in 1983. That’s more than a decade before the Large Hadron Collider was built. Neener neener.

(6) A tokamak is “a machine producing a toroidal magnetic field for confining a plasma” and is one of several types of magnetic confinement devices, such as that used for the JET. There must be naughty uber-nerd jokes about “magnetic confinement.” It’s not just my warped mind or anything, right?

(7) The Bussard Interstellar Ramjet is a theoretical spacecraft using fusion for propulsion and proposed in 1960 by physicist Robert W. Bussard. Science fiction writer Larry Niven popularized this method of space travel in his Known Space series of books. Carl Sagan also referenced this method in his Cosmos television series. Can’t…resist…must..say it… BILLIONS and BILLIONS. (Yes, I went there. After #6, this surprises you?)

(8) The Bussard Ramjet uses enormous electromagnetic fields as a scoop to collect and compress hydrogen from the gas and dust that fill the space between stars. “High speed forces the reactive mass into a progressively constricted magnetic field, compressing it until thermonuclear fusion occurs. The magnetic field then directs the energy as rocket exhaust opposite to the intended direction of travel, thereby accelerating the vessel.” (quote via Wikipedia)

(9) Inertial electrostatic confinement (IEC) uses an electrostatic field to contain fusion plasma. This type of reactor is cheap to build, costing a few thousand dollars. While popular with hobbyists, the process has yet to produce power. A promising new concept called Periodically Oscillating Plasma Sphere (POPS) has been proposed that would mitigate power loss and might produce cheap fusion power. I’m all of out of naughty plasma containment jokes (but I welcome them in the comments).

(10) Bigger is better? Larger than JET, the International Thermonuclear Experimental Reactor (ITER) is a magnetic confinement fusion reactor to be built in France and expected to produce its first plasma operation in 2018.

(11) Scientists are currently trying to build a rocket that utilizes the “charged debris from a proton/anti-proton annihilation” for propulsion. Essentially, fling a proton and an anti-proton at one another, capture the pions expelled from the reaction, and use the energy of these charged particles for thrust. I suspect this is something Sheldon from the Big Bang Theory attempted for his 6th grade science fair project. (This isn’t fusion, but bear with me, keep reading.)

(12) A antimatter-catalyzed fusion reaction could be used to power propulsion. A small amount of anti-protons are fired at a “fusion target” or nuclear fuel. The reaction heats the nuclear fuel enough to cause thermonuclear fusion. Evidently, this method could never produce enough power to be used as alternative energy source here on Earth, but it could theoretically power rockets and ships in space without the need to transport massive amounts of raw fuel. Is that sort of like when I eat chocolate and it catalyzes fat into some kind of thermonuclear fusion evidenced by the number on my bathroom scale?

(13) Time in a magnetic bottle. A Penning Trap collects anti-protons in a magnetic bottle, where the particles are kept cold by liquid nitrogen, helium and a stable magnetic field. (Also see this article for more information on how a Penning Trap might be used in an antimatter-catalyzed fusion reaction.)

Amazon Listmania for Science Fiction novels dealing with nuclear fusion.

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For Eric