Featured Research

from universities, journals, and other organizations

Stars, jets and batteries: Multi-faceted magnetic phenomenon confirmed in the laboratory for the first time

Date:
June 20, 2012
Source:
Helmholtz Association of German Research Centres
Summary:
Magnetic instabilities play a crucial role in the emergence of black holes and other cosmic phenomena. The confirmation of such a magnetic instability – the Tayler instability – was successfully achieved for the first time. The findings should be able to facilitate construction of large liquid-metal batteries, which are under discussion as cheap storage facilities for renewable energy.

The Tayler instability also affects large-scale liquid metal batteries, which, in the future, could be used for renewable energy storage.
Credit: Tom Weier, Institut für Fluiddynamik, HZDR

Magnetic instabilities play a crucial role in the emergence of black holes, they regulate the rotation rate of collapsing stars and influence the behavior of cosmic jets. In order to improve understanding of the underlying mechanisms, laboratory experiments on earth are necessary. At the Helmholtz- Zentrum Dresden-Rossendorf (HZDR), confirmation of such a magnetic instability -- the Tayler instability -- was successfully achieved for the first time in collaboration with the Leibniz Institute for Astrophysics in Potsdam (AIP). The findings should be able to facilitate construction of large liquid-metal batteries, which are under discussion as cheap storage facilities for renewable energy.

The Tayler instability is being discussed by astrophysicists in reference to, among other things, the emergence of neutron-stars. Neutron stars, according to the theory, would have to rotate much faster than they actually do. The mysterious braking-effect has meanwhile been attributed to the influence of the Tayler instability, which reduces the rotation rate from 1,000 rps down to approximately 10 to 100 rps. Structures similar in appearance to the double-helix of DNA have been occasionally observed in cosmic jets, i.e. streams of matter, which emanate vertically out of the rotating accretion discs near black holes.

Liquid Metal Batteries -- Energy Storage Facilities for the Future?

The magnetic phenomenon, observed for the first time in the laboratory at the Helmholtz-Zentrum Dresden-Rossendorf, was predicted in theory by R.J. Tayler in 1973. The Tayler instability always appears when a sufficiently strong current flows through an electrically conductive liquid. Starting from a certain magnitude, the interaction of the current with its own magnetic field creates a vortical flow structure. Ever since their involvement with liquid-metal batteries, HZDR scientists have been aware of the fact that this phenomenon can take effect not only in space but on earth as well. The future use of such batteries for renewable energy storage would be more complicated than originally thought due to the emergence of the Tayler instability during charging and discharging.

American scientists have developed the first prototypes and assume that the system could be easily scaled up. The HZDR physicist Dr. Frank Stefani is skeptical: "We have calculated that, starting at a certain current density and battery dimension, the Tayler instability emerges inevitably and leads to a powerful fluid flow within the metal layers. This stirs the liquid layers, and eventually a short circuit occurs." In the current edition of the "Physical Review Letters," the team directed by Stefani -- together with colleagues from AIP led by Prof. Günther Rüdiger -- reported on the first successful experiment to prove the Tayler instability in a liquid metal. Here a liquid alloy at room temperature consisting of indium, gallium and tin is deployed, through which a current as high as 8,000 amps is sent. In order to exclude other causes for the observed instability such as irregularities in conductivity, the researchers intentionally omitted the implementation of velocity sensors; instead, they used 14 highly-sensitive magnetic field sensors. The data collected indicate the growth rate and critical streaming effects of the Tayler instability, and these data remarkably correspond to the numerical predictions.

How liquid batteries work

In the context of the smaller American prototypes the Tayler instability does not occur at all, but liquid batteries have to be quite large in order to make them economically feasible. Frank Stefani explains: "I believe that liquid-metal batteries with a base area measured in square meters are entirely possible. They can be manufactured quite easily in that one simply pours the liquids into a large container. They then independently organize their own layer structure and can be recharged and discharged as often as necessary. This makes them economically viable. Such a system can easily cope with highly fluctuating loads." Liquid-metal batteries could thus always release excessive-supply current when the sun is not shining or the wind turbines are standing still.

The basic principle behind a liquid-metal battery is quite simple: since liquid metals are conductive, they can serve directly as anodes and cathodes. When one pours two suitable metals into a container so that the heavy metal is below and the lighter metal above, and then separates the two metals with a layer of molten salt, the arrangement becomes a galvanic cell. The metals have a tendency to form an alloy, but the molten salt in the middle prevents them from direct mixing. Therefore, the atoms of one metal are forced to release electrons. The ions thus formed wander through the molten salt. Arriving at the site of the other metal, these ions accept electrons and alloy with the second metal. During the charging process, this process is reversed and the alloy is broken up into its original components. In order to avoid the Tayler instability within big batteries -- meaning a short circuit -- Stefani suggests an internal tube through which the electrical current can be guided in reverse direction. This allows the capacity of the batteries to be considerably increased.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal References:

  1. Martin Seilmayer, Frank Stefani, Thomas Gundrum, Tom Weier, Gunter Gerbeth, Marcus Gellert, Günther Rüdiger. Experimental Evidence for a Transient Tayler Instability in a Cylindrical Liquid-Metal Column. Physical Review Letters, 2012; 108 (24) DOI: 10.1103/PhysRevLett.108.244501
  2. Frank Stefani, Tom Weier, Thomas Gundrum, Gunter Gerbeth. How to circumvent the size limitation of liquid metal batteries due to the Tayler instability. Energy Conversion and Management, 2011; 52 (8-9): 2982 DOI: 10.1016/j.enconman.2011.03.003

Cite This Page:

Helmholtz Association of German Research Centres. "Stars, jets and batteries: Multi-faceted magnetic phenomenon confirmed in the laboratory for the first time." ScienceDaily. ScienceDaily, 20 June 2012. <www.sciencedaily.com/releases/2012/06/120620113228.htm>.
Helmholtz Association of German Research Centres. (2012, June 20). Stars, jets and batteries: Multi-faceted magnetic phenomenon confirmed in the laboratory for the first time. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2012/06/120620113228.htm
Helmholtz Association of German Research Centres. "Stars, jets and batteries: Multi-faceted magnetic phenomenon confirmed in the laboratory for the first time." ScienceDaily. www.sciencedaily.com/releases/2012/06/120620113228.htm (accessed April 24, 2014).

Share This



More Matter & Energy News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) — The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Air Force: $4.2B Saved from Grounding A-10s

Air Force: $4.2B Saved from Grounding A-10s

AP (Apr. 23, 2014) — Speaking about the future of the United States Air Force, Chief of Staff Gen. Mark Welsh says the choice to divest the A-10 fleet was logical and least impactful. (April 23) Video provided by AP
Powered by NewsLook.com
Jets Fuel Jump in Boeing's Revenue

Jets Fuel Jump in Boeing's Revenue

Reuters - Business Video Online (Apr. 23, 2014) — A sharp rise in revenue for commercial jets offset a decline in Boeing's defense business. And a big increase in deliveries lifted profitability. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) — South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins