With stimulus aid, scientists hope to mimic nature's dynamos

Oct 09, 2009 by Terry Devitt

(PhysOrg.com) -- In the cosmos, all celestial objects - planets, stars, galaxies and clusters of galaxies - have magnetic fields. On Earth, the magnetic field of our home planet is most easily observed in a compass where the needle points north.

But the origin of magnetic fields in the universe — including Earth's — remains a puzzle of cosmology despite many determined efforts by scientists to ferret out the secrets of how they first arose. Now, with the help of $2.4 million in stimulus funding from the National Science Foundation, University of Wisconsin-Madison scientists will attempt to generate a magnetic field in precisely the same fashion as a planet or galaxy: by building and operating a plasma dynamo to explore the self-generation of magnetic fields.

"We don't know why there are magnetic fields in the universe," says UW-Madison professor of astronomy Ellen Zweibel, who, along with UW-Madison physics professor Cary Forest, will lead the new initiative. "They didn't come out in the Big Bang. We don't know how they originated or are sustained."

The crucible for the study of cosmic magnetic fields will be the Plasma Dynamo Facility in Sterling Hall, the heart of which will be a three-meter diameter spherical vessel that will contain the same kind of plasmas observed in space. Plasmas, sometimes referred to as the fourth state of matter, are superheated gases where the atoms that make up the gas have been stripped of all of their electrons leaving behind a conducting, highly electrified collection of and free electrons.

The sun, for example, is a plasma and, ironically, were it not for the Earth's magnetic field, the solar winds generated by the sun would scorch our planet. The atmosphere of Mars, some scientists think, was blasted away by when its dynamo stopped.

Zweibel notes that there are important distinctions between planetary dynamos, which are generated typically in the molten metal at the core of a planet, and the dynamos in stars and galaxies, which are powered by plasmas. Both, however, generate critical magnetic fields, and what sparked the different types of dynamos is unknown in both instances.

"This plasma dynamo experiment will allow us to study for the first time in the laboratory how plasma can put energy into a instead of taking energy out," adds Forest, an expert on nature's dynamos who has built similar devices that use molten metal instead of plasma to spontaneously generate magnetic fields. Now, the only way scientists can study astrophysical plasmas is by observing and taking spectra from stars and other objects, and through the occasional direct sampling of a plasma by spacecraft designed to scoop up particles in space.

The plasma dynamo facility will be the first of its kind in the world and promises to take the quest for the secrets of the magnetic fields in the universe to another level: "The ability to pull out features in plasmas that are not present in the simpler liquid metal systems is the key," says Zweibel, an expert in plasma astrophysics.

Provided by University of Wisconsin-Madison (news : web)

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

add to favorites email to friend print save as pdf

Related Stories

The Dynamo in the Cornfield

Jan 05, 2005

To understand our planet's magnetic field, Wisconsin scientists are studying a ball of molten metal In an underground bunker that brushes up against a barnyard on one side and a cornfield on the other, scienti ...

How space eruptions happen

Apr 07, 2009

(PhysOrg.com) -- Mathematicians at the University of St Andrews have made a discovery which could lead to a better understanding of why huge eruptions occur in space.

Creation of a magnetic field in a turbulent fluid

Mar 10, 2007

Understanding the origin and behavior of the magnetic fields of planets and stars is the goal of research being carried out by many teams from all over the world. The VKS collaboration (CEA, CNRS, Ecole normale supérieure ...

Physicist confines plasma components in a trap within a trap

May 06, 2008

A University of Michigan professor has taken a step toward simulating a type of matter found in the crusts of neutron stars, in the cores of gas giant planets, and in exotic plasmas thought to be present in the earliest universe.

Mars magnetic field mystery explained

Sep 25, 2008

(PhysOrg.com) -- So much attention has been paid to the similarities and differences between Earth and Mars that we often look to the ancient red planet for signposts in our own planet's future. A U of T physicist, ...

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.