Z fires objects faster than Earth moves through space

Technique helps compute Jupiter/Saturn mass, improve peacetime fusion capsule design, stabilize stockpile

Sandia National Labs has accelerated a small plate from zero to 76,000 mph (122,360 km/hr) in less than a second.
The speed of the thrust was a new record for Sandia's Z Machine - sometimes referred to as the fastest gun in the West. Actually the fastest in the world, it is now able to propel small plates at 34 kilometers a second, faster than the 30 km/sec that Earth travels through space in its orbit about the sun, 50 times faster than a rifle bullet, and three times the velocity needed to escape Earth's gravitational field.

Image: ARE YOU GOOD FOR ANOTHER 15 KM/SEC? — Sandia researcher Marcus Knudson considers his favorite apparatus: the Z insert that sends flyer plates hurling at phenomenal speeds. (Photo by Randy Montoya)

The immediate purpose of these very rapid flights is to help understand the extreme conditions found within the interiors of the giant planets Saturn and Jupiter, hasten the achievement of virtually unlimited energy through peacetime atomic fusion, and provide more information about the condition of the U.S. nuclear stockpile without having to explode a nuclear weapon.

"This is one of the few ways on earth to get hard information on problems at the outer reaches of science, rather than having to rely on complex speculations that may or may not be correct," says Marcus Knudson, lead scientist on the effort.

Z's hurled plates strike a target after traveling only five millimeters. The impact generates a shock wave - in some cases, reaching 15 million times atmospheric pressure - that passes through the target material. The waves are so powerful that they turn solids into liquids, liquids into gases, and gases into plasmas in the same way that heat melts ice to water or boils water into steam.

The difference is that the process takes place at far higher temperatures and in much shorter times than the kitchen stove could ever approach. The pressures produce states of materials rarely seen or measured in the laboratory. Says Yogi Gupta, a professor known for his work in shock physics at the Washington State University in Pullman, "If you had asked me a few years ago if we could send something this fast, I would have said you were joking. But mankind is always trying to create conditions in the laboratory that imitate extreme conditions [found elsewhere]."

When shock waves penetrate a capsule containing deuterium (an isotope of hydrogen), researchers learn more about how hydrogen behaves under extreme conditions, providing more information for humanity's effort to eventually achieve controlled nuclear fusion, the process that drives the sun. Harnessed in a power plant, this potentially low-environmental-impact method could achieve virtually unlimited energy from sea water.

By creating states of matter extremely difficult to achieve on Earth, the flyer plates also provide hard data to astrophysicists speculating on the structure and even the formation of planets like Jupiter and Saturn. Says Didier Saumon, an astrophysicist at Los Alamos National Laboratory, "The internal structures of Jupiter and Saturn are composed mostly of hydrogen, so knowing its equation of state [how hydrogen and its isotopes behave at pressures from one to 50 million atmospheres] is highly relevant to how we infer the interior properties of these planets. Z gave us hard data."

A paper on the flyer plate results, first presented in a technical talk to the American Physical Society, has been submitted to the Journal of Applied Physics.

The plates are small - only 30 mm by 15 mm in cross-section, and 850 microns thick. The trick in accelerating the fragile aluminum plates at 10-to-the-10th Gs (force of Earth's gravity) without vaporizing them lies in the finer control now achievable of the magnetic field pulse driving the flight.

The arrival of energy at the target is staggered over three hundred nanoseconds, so that the amperage arrives less like a brick wall that would vaporize the plate and more in controllable increments.

This requirement was better achieved by a recent upgrade that removed a single laser formerly used to trigger current in Z's thirty-six cables simultaneously. In its place, 36 laser switches were installed - one for each cable. This change permits researchers to shape the electrical pulse that arrives at the target, with a corresponding modulation in the magnetic field driving the plate.

An upgrade of Z planned for next year is expected to achieve plate velocities of 45 to 50 km/sec, says Marcus, driving targeted materials further into their plasma regime.

Z's former record in propelling plates was 21 km/sec, set two years ago.

Source: Sandia National Labs

Related stories:

Plate tectonics started over 4 billion years ago, geochemists report
(PhysOrg.com) -- A new picture of the early Earth is emerging, including the surprising finding that plate tectonics may have started more than 4 billion years ago — much earlier than scientists had believed, according to new research by UCLA geochemists reported Nov. 27 in the journal Nature.
Glacial Erosion Changes Mountain Responses To Plate Tectonics
(PhysOrg.com) -- Intense glacial erosion has not only carved the surface of the highest coastal mountain range on earth, the spectacular St. Elias range in Alaska, but has elicited a structural response from deep within the mountain.
Deepest living fishes caught on camera for the first time
(PhysOrg.com) -- Scientists filming in one of the world's deepest ocean trenches have found groups of highly sociable snailfish swarming over their bait, nearly five miles (7700 metres) beneath the surface of the Pacific Ocean. This is the first time cameras have been sent to this depth.

Researchers find oldest rocks on Earth
Canadian bedrock more than four billion years old may be the oldest known section of the Earth's early crust. Scientists at the Carnegie Institution used geochemical methods to obtain an age of 4.28 billion years for samples of the rock, making it 250 million years more ancient than any previously discovered rocks. The findings, which offer scientists clues to the earliest stages of our planet's evolution, are published in the September 26 issue of Science.
Diamonds show how Earth is recycled
(PhysOrg.com) -- Tiny minerals found inside diamonds have provided us with a rare glimpse of the Earth’s deepest secrets. This exciting new research by a team of scientists, led by the University of Bristol, is reported today (30 July) in Nature.
China quake rare and unexpected, new study says
A new analysis of the setting for last month's devastating earthquake in China by a team of geoscientists at MIT shows that the quake resulted from faults with little seismic activity, and that similar events in that area occur only once in every 2,000 to 10,000 years, on average.
Beaded viruses and geology-inspired paintings show the art in science
Holly Wichman found herself an empty-nester with a well-established research lab in 2000, so she used some of her new found time to pursue an artistic activity that paralleled her research. The virologist began making small beaded sculptures in the shapes of viruses that she studies in her lab. Wichman's beaded viruses along with artworks by two other scientists will be displayed at the American Association for the Advancement of Science Gallery starting 16 June.
Mountain ranges rise much more rapidly than geologists expected
Mountains may experience a "growth spurt" that can double their heights in as little as two to four million years—several times faster than the prevailing tectonic theory suggests.

News discussion:

Physics news