Breakthrough Technique Might Unlock the Secrets of Plasmas

UBC researchers have developed a technique that brings scientists a big step closer to unlocking the secrets of the most abundant form of matter in the universe.

Plasmas-or ionized gas-can be found in fluorescent light bulbs, thermonuclear explosions, the Earth's upper atmosphere, lightning bolts, and virtually all stars.

In the lab, cold plasmas have always been made by cooling trapped atoms to a fraction of a degree above absolute zero, to form clouds of ions and electrons that are nearly standing still. Now, for the first time, UBC researchers have found a way to make ultra-cold plasmas out of molecules.

Starting with a gaseous sample cooled in a supersonic molecular beam, a team led by Ed Grant, Head of the Department of Chemistry, has formed a plasma of nitric oxide that has ion and electron temperatures as cold as plasmas made from trapped atoms.

The plasmas are also surpisingly long-lived (30 microseconds or more) eventhough molecular ions can quickly dissociate by recombining with electrons.

"It's amazing that our plasmas have sustained life at all," says Grant. "We think that the high charged particle density we create interferes with ion-electron recombination."

Their technique, detailed in the current issue of the journal Physical Review Letters, not only produces plasmas three orders of magnitude denser than those made with trapped atoms, but appears to reach much higher levels of correlation, a factor describing the onset liquid-like collective motion.

"Molecules represent a holy grail of ultra-cold science," says Grant. "The ability to break out of the atom 'trap' is tremendously liberating and could lead to a whole new field of physics."

Grant adds that further understanding of ultra-cold plasma on a molecular level could lead to new knowledge about gas planets like Jupiter, White Dwarf stars, thermonuclear fusion, and X-ray lasers.