Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stellar magnetism: What's behind the most brilliant lights in the sky?

31.01.2018

Space physicists at University of Wisconsin-Madison have just released unprecedented detail on a bizarre phenomenon that powers the northern lights, solar flares and coronal mass ejections (the biggest explosions in our solar system).

The data on so-called "magnetic reconnection" came from a quartet of new spacecraft that measure radiation and magnetic fields in high Earth orbit.


Jan Egedal, professor of physics at UW-Madison who lead an exploration of magnetic reconnection, stands beside a chamber used for experiments in that exotic phenomenon. Magnetic reconnection seems to be involved in some of the most violent explosions in the universe; the recent study was the clearest view of the magnetic reconnection ever measured in space. The results "blew my mind," he says.

Credit: David Tenenbaum/UW-Madison


Top: Electron movement in solar wind parallels magnetic field direction. Bottom: After magnetic reconnection, the electrons lose their alignment with Earth's magnetic field.

Credit: UW-Madison

"We're looking at the best picture yet of magnetic reconnection in space," says Jan Egedal, a professor of physics and senior author of a study in Physical Review Letters. Magnetic reconnection is difficult to describe, but it can be loosely defined as the merger of magnetic fields that releases an astonishing amount of energy.

Magnetic reconnection remains mysterious, especially since it "breaks the standard law" governing charged particles, or plasma, Egedal says.

Egedal and colleagues studied recordings from Oct. 15, 2016, when the Magnetosphere Multiscale satellite passed through the point where the solar wind meets Earth's magnetic field. "Our data clearly show that electrons suddenly cease to follow magnetic fields and zoom off in another direction, corkscrewing and turning. That begs for explanation," Egedal says.

The activity confirmed the theoretical descriptions of magnetic reconnection. But it violated the standard law governing the behavior of plasmas - clouds of charged particles that comprise, for example, the solar wind. "The 'plasma frozen-in law' says electrons and magnetic fields have to move together always, and suddenly that does not apply here," says Egedal. "It's the clearest example ever to be measured in space, and it blew my mind."

"Our equations tell you reconnection cannot happen, but it does," Egedal says, "and our results show us which factors need to be added to the equations. When the law is violated, we can get an explosion. Even in Earth's moderate magnetic field, reconnection from an area just 10 kilometers across can change the motion of plasma thousands of kilometers distant."

In the 1970s, telescopes orbiting above earth's sheltering magnetic field and atmosphere began returning data on X-rays and other non-visible types of radiation. Rather quickly, the age-old image of the sky as a quiet curtain of stars was yanked aside, revealing a zoo of weird objects, powerful beams and cataclysmic explosions.

All of them needed to be explained, and theorists began to focus on magnetic reconnection, which had been sketched out in 1956. By now, magnetic reconnection has been linked to:

  • Black holes, ultra-dense objects with intense gravity that prohibits even light from leaving.

     

  • Pulsars, which rotate hundreds of times a second and emit piercing beacons of light.

     

  • Supernovas, which release energy visible across the galaxies when they explode.

     

  • Active galactic nuclei, super-bright candles that are visible from billions of light years distance.

"Almost everything we know about the universe comes from the light that reaches us," says Cary Forest, also a professor of physics at UW-Madison. "When one of these fantastic space telescopes sees a massive burst of X-rays that lasts just tens of milliseconds coming from an object in a galaxy far away, this giant burst of energy at such a great distance may reflect a massive reconnection event."

But there's more, Forest adds. "When neutron stars merge and give off X-rays, that's magnetic reconnection. With these advanced orbiting telescopes, just about everything that's interesting, that goes off suddenly, probably has some major reconnection element at its root."

Magnetic reconnection also underlies the auroras at both poles, Egedal says. When reconnection occurs on the sunward side of Earth, as was seen in the recent study, "it changes the magnetic energy in the system. This energy migrates to the night side, and the same thing happens there, accelerating particles to the poles, forming auroras."

Beyond offering insight into the role of magnetic reconnection in celestial explosions, eruptions and extraordinary emissions of energy, the observations have a practical side in terms of space weather: explosions of charged matter from the sun can damage satellites and even electrical equipment on the ground. After a solar flare in 1989, for example, the entire power system in Quebec went dark after it picked up a pulse of energy from space. "Across the United States from coast to coast, over 200 power grid problems erupted within minutes of the start of the March 13 magnetic storm," NASA wrote.

Today, Forest notes, modern utility systems contain switches to interrupt the loop of conductors that could become antennas that pick up a problematic pulse from the sun.

"If we understand reconnection better, perhaps we can improve space weather forecasts," says Egedal. "We can look at the sun to predict what may happen in two to four days, which is how long the wind from the sun takes to reach Earth."

###

-- David Tenenbaum, 608-265-8549, djtenenb@wisc.edu

-The work was supported by National Science Foundation (NSF) GEM award 1405166 and NASA grant NNX14AL38G. Simulations used NASA HEC and LANL IC resources.

Media Contact

Jan Egedal
egedal@wisc.edu
608-262-3628

 @UWMadScience

http://www.wisc.edu 

Jan Egedal | EurekAlert!

More articles from Physics and Astronomy:

nachricht APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied 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: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>