A metal wire is heated when a current runs through it. A 25-µm thick molybdenum wire carrying 105 amps is vaporized into a plasma, and the magnetic field generated by the current compresses that plasma. Cross two such wires and at their juncture you get an x-pinch—a 1- to 2-micron region of 107 °C plasma that emits x rays of energy greater than 2.5 keV for less than a nanosecond. Now, researchers at Cornell University’s Laboratory of Plasma Studies have used such x-ray point sources to generate few-micron-resolution radiographs of tiny objects such as the housefly (bottom) and its wing shown here, using phase-contrast imaging. For more on the imaging technique, see July 2000, page 23. Several x-pinch results were presented in November at the American Physical Society’s Division of Plasma Physics meeting. (Papers RP1.101-104 and UI2.001.)
