Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

International collaboration replicates amplification of cosmic magnetic fields

02.06.2014

Astrophysicists have established that cosmic turbulence could have amplified magnetic fields to the strengths observed in interstellar space.

"Magnetic fields are ubiquitous in the universe," said Don Lamb, the Robert A. Millikan Distinguished Service Professor in Astronomy & Astrophysics at the University of Chicago. "We're pretty sure that the fields didn't exist at the beginning, at the Big Bang. So there's this fundamental question: how did magnetic fields arise?"


This video simulation shows how a laser that illuminates a small carbon rod launches a complex flow, consisting of supersonic shocks and turbulent flow. When the grid is present, turbulence becomes dominant and the self-generated magnetic field is significantly amplified. The top half of the simulation illustrates gas density per cubic centimeter, while the bottom half depicts strength of magnetic field.

Credit: University of Chicago Flash Center

Helping to answer that question, which is of fundamental importance to understanding the universe, were millions of hours of supercomputer simulations at Argonne National Laboratory. Lamb and his collaborators, led by scientists at the University of Oxford, report their findings in an article published in the June 1 issue of Nature Physics.

The paper describes experiments at the Vulcan laser facility of the United Kingdom's Rutherford Appleton Laboratory that recreates a supernova (exploding star) with beams 60,000 billion times more powerful than a laser pointer. The research was inspired by the detection of magnetic fields in Cassiopeia A, a supernova remnant, which are approximately 100 times stronger than those in adjacent interstellar space.

Physics at multiple scales

"It may sound surprising that a tabletop laboratory experiment that fits inside an average room can be used to study astrophysical objects that are light years across," said Gianluca Gregori, professor of physics at Oxford. "In reality, the laws of physics are the same everywhere, and physical processes can be scaled from one to the other in the same way that waves in a bucket are comparable to waves in the ocean. So our experiments can complement observations of events such as the Cassiopeia A supernova."

Making the advance possible was the extraordinarily close cooperation between Lamb's team at UChicago's Flash Center for Computational Science and Gregori's team of experimentalists.

"Because of the complexity of what's going on here, the simulations were absolutely vital to inferring exactly what's going on and therefore confirming that these mechanisms are happening and that they are behaving in the way that theory predicts," said Jena Meinecke, graduate student in physics at Oxford and lead author of the Nature Physics paper.

Magnetic fields range from quadrillionths of a gauss in the cosmic voids of the universe, to several microgauss in galaxies and galaxy clusters (ordinary refrigerator magnets have magnetic fields of approximately 50 gauss). Stars like the sun measure thousands of gauss. Neutron stars, which are the extremely compact, burned out cores of dead stars, exhibit the largest magnetic fields of all, ones exceeding quadrillions of gauss.

In 2012, Gregori's team successfully created small magnetic fields, called "seed fields," in the laboratory via an often-invoked effect called the Biermann battery mechanism. But how could seed fields grow to gigantic sizes in interstellar space? Building on their earlier findings, Gregori and his collaborators at 11 institutions worldwide now have demonstrated the amplification of magnetic fields by turbulence.

In their experiment, the scientists focused laser beams onto a small carbon rod sitting in a chamber filled with a low-density gas. The lasers, generating temperatures of a few million degrees, caused the rod to explode, creating a blast that expanded throughout the gas.

"The experiment demonstrated that as the blast of the explosion passes through the grid it becomes irregular and turbulent, just like the images from Cassiopeia," Gregori said.

Experimental variables

"The experimentalists knew all the physical variables at a given point. They knew exactly the temperature, the density, the velocities," said UChicago research scientist Petros Tzeferacos, a study co-author. Tzeferacos and his colleagues incorporated that data into their FLASH simulations.

"This allows us to benchmark the code against something that we can see," Tzeferacos said. Such benchmarking—called validation—shows that the simulations can reproduce the experimental data. The simulations consumed 20 million processing hours on both the Mira and Intrepid supercomputers at Argonne. Mira, which can perform 10 quadrillion calculations per second, is 20 times faster than Intrepid.

With validation in hand, all members of the collaboration could return repeatedly to the simulations to get answers to new questions regarding the physics they saw. "We could look at the velocity instead of the density of the magnetic field, or we might look at the pressure," Lamb said. "This simulation is a treasure trove of information about what's really going on. It's actually critical to understanding correctly what's really happening."

###

The magnetic field simulations were made possible by the addition of capabilities to the FLASH Code in recent years, funded by the Office of Advanced Simulation and Computing in the Department of Energy's National Nuclear Security Agency. Originally designed to support computer simulations of exploding stars, FLASH Code also now supports high-energy density physics simulations to better understand the properties of matter at high densities and high temperatures.

Citation:

"Turbulent amplification of magnetic fields in laboratory laser-produced shock waves," by J. Meinecke and 26 others, Nature Physics, June 1, 2014.

Funding:

U.S. Department of Energy through the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program.

Steve Koppes | Eurek Alert!

Further reports about: Cassiopeia Computational Magnetic Nature Oxford amplification interstellar physics waves

More articles from Physics and Astronomy:

nachricht Spintronics: Researchers show how to make non-magnetic materials magnetic
06.08.2020 | Martin-Luther-Universität Halle-Wittenberg

nachricht Manifestation of quantum distance in flat band materials
05.08.2020 | Institute for Basic Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>