A new tabletop device said togenerate a long-sought laboratory version of nuclear fusion has been calledinto question even before it was formally announced.

The device was created inresearch led by Rusi Taleyarkhan at the Oak Ridge National Laboratory. A paperabout the new process will be published March 8 in the journal Science. But in an unusual prepublicationstep Monday, the journal released new information, provided by otherresearchers at the same laboratory who say the technique does not work.

Nuclear fusion is a process thatjoins atoms together. Inside the Sun, for example, hydrogen is fused to createheavier elements. In the process, energy is released.

A different type of nuclearreaction, called fission, was long ago harnessed to create the atomic bomb andis used in nuclear power plants. Fission splits heavy atoms, such as uranium,to release energy.

Scientists have understood fusionsince the early 1900s, and for many decades they have tried unsuccessfully torecreate this process in labs. Commercial fusion could solve the world's powerwoes, some scientists have long claimed, and it would do so safely, with littleor no harmful byproducts like the radioactive waste that comes from fission.

Many schemes have been developed,from using magnetism to lasers to create high-speed, high-temperaturecollisions among atoms. Other so-called "cold fusion" efforts werewidely reported but never reproduced, and therefore scientists considered themflawed.

The new device uses sound wavesand bubbles.

"In such a device, a smallgas bubble trapped in liquid is imploded using high pressure sound waves,"explains Fred Becchetti, a University of Michigan scientist who wrote ananalysis of the new technique Science."The imploding bubble reaches sufficiently high temperatures and pressuresto emit a burst of light."

The device created a bubble thatreached 10 million degrees Kelvin -- as hot as the center of the Sun -- andalso appears to have emitted high-energy neutrons, similar to neutrinos thatare produced by the Sun. These neutrons are the telltale sign of fusion.

Taleyarkhan and his colleaguessay in their original paper that their results only suggest, but do notconfirm, that the bubbles' collapse generated nuclear fusion.

Prior to the Monday developments,Becchetti told SPACE.com that unlikepast efforts, Taleyarkhan and colleagues "are not operating in secret andare making details public, in a peer-reviewed article." He added thatother scientists should be able to "repeat the experiment and eitherconfirm the results reported" or not.

Some other Oak Ridge researcherstried just that.

Using the same device, DanShapira and Michael Saltmarsh report in a paper published online Monday by Science that they found "noevidence" for the telltalehigh-energy neutrons.

Taleyarkhan's team responded, inyet another online Science paper,that Shapira and Saltmarsh did, in fact, detect neutron emissions, but hadimproperly calibrated their detector and therefore misinterpreted the findings.

Taleyarkhan's group, nonetheless,still agrees further study is needed.

If the apparatus turns out towork, Becchetti said its greatest promise might not be in leading to commercialfusion. Instead, he said, it would be a useful research tool for exploring whatgoes on inside the Sun.