Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vacuum arcs spark new interest

08.11.2010
News from the 52nd annual meeting of the APS Division of Plasma Physics

Whenever two pieces of metal at different voltages are brought near each other, as when an appliance is plugged into a live socket, there is a chance there will be an arc between them.


Even in a vacuum, voltages can literally tear metal apart. Current research is using molecular dynamics to show what happens at the atomic level when material is damaged by arcing in vacuum. Credit: J. Norem, Z. Insepov, Th. Proslier, D. Huang, S. Mahalingam, and S. Veitzer

Most of the arcs people see are a breakdown of the gas between the metal surfaces, but this type of breakdown can also occur in a vacuum. This vacuum breakdown, which until recently has not been well understood, has implications for applications from particle accelerators to fusion reactors.

As part of an effort to understand the maximum accelerating field in particle accelerators, scientists at Argonne National Laboratory have been modeling the processes involved in vacuum breakdown. Now, a new model of this phenomenon is beginning to reveal what is happening in these arcs, and scientists are studying a number of new phenomena associated with them.

In this new model, the breakdown arc is triggered by the electric field in the vacuum gap literally tearing the metal apart. (The same force that causes "static cling" can be very powerful for high electric fields, particularly at tiny corners, and in cracks where the fields are intensified by the local geometry of the surface.) After the metal is torn apart, the fragments should become ionized and form microscopic plasmas that are very dense and cold (for a plasma). Because of the high densities in these plasmas, the surface fields inside the arc quickly become even stronger than they were at breakdown. The arc becomes very damaging to the metal surface over a comparatively large area, eventually leaving a pit that should be visible to the naked eye.

While this model seems to be internally consistent, researchers want to use it to produce predictions that can be verified experimentally. Current research is using molecular dynamics to show what happens at the atomic level when the material is torn apart, plasma modeling codes to show how the plasma initially forms and what its properties are, and electrohydrodynamics to show how the surface of the arc pit is affected. While current results seem generally consistent with existing experimental measurements, more precise tests are being developed.

In principle, a better understanding of the precise causes of electrical breakdown should suggest solutions that are relevant to fusion reactors and space communications, among other things.

Saralyn Stewart | EurekAlert!
Further information:
http://www.utexas.edu

More articles from Physics and Astronomy:

nachricht New type of smart windows use liquid to switch from clear to reflective
14.12.2017 | The Optical Society

nachricht New ultra-thin diamond membrane is a radiobiologist's best friend
14.12.2017 | American Institute of Physics

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

Guardians of the Gate

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>