Breakthrough In Nuclear Fusion

So, 64 years ago, started a story in Electronics Weekly’s edition of October 26th 1950.

The story continued:

Experience up to now  has shown that to produce and sustain such fields requires enormous amounts of power and an extremely elaborate cooling system.

Departing from the traditional approach. John R. Purcell, Errol Payne and their associates in the Cryogenic Engineering Laboratory （CEL) of the National Bureau of Standards Boulder, Colorado, propose the use of a low-temperature  operation and an entirely diferent type of electromagnet. 

The prospects suggest a major breakthrough in nuclear fusion work.

The CEL is exploring several methods of producing a low-power,steady-state electromagnet with a 100.000-gauss field intensity. (The earth’s magnetic field is about 1/2 gauss). 

If successtul, this magnet will serve as a pilot model in the design of electromagnets with field intensities great enough to contain, the temperatures generated by a nuclear fusion reaction.

One current effort at CEL is through designs based on the superconductivity of certain metals and alloys at cryogenic（down to -453° F.) temperatures. 

Since material in the superconducting state shows no resistance to electricity, several major problems of construction and operation of electromagnets are eliminated.

For example, electromagnets of conventional design require a constant and tremendous supply of power. A superconducting magnet needs only a short-time application of power to establish its field. 

Anotherfactor absent in superconducting electromagnets is the heat generated by large currents supplied for any length of time to the coil-winding of conventional electromagnets.

Unfortunately, large currents or applied external magnetic fields have the ability to quench superconductivity.

Resistance reappears in amounts characteristic of the normal metal or alloy. To date, no method has been found to prevent this quenching