Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Revealed: The secret of plasma heating

29.08.2008
Researchers at the Ruhr University in Bochum (RUB) discover mechanism for energy coupling

The secret of electron heating in low temperature plasmas has been discovered by the Bochum researchers at the Center of Excellence “Plasma Science and Technology” (CPST) at the Ruhr University – who have thereby found the answer to the question which has been puzzling scientists for decades of why particularly the electrons in such plasmas are so hot.

The non-linear behavior of the boundary sheath causes the electric current flowing in the plasma to oscillate. This results in an increase of the electrical current, and thus in the heating of the plasma. This previously unknown mechanism called “non-linear electron resonance heating” is the subject of a report by researchers in the current issue of the world's foremost physics letters journal "Physical Review Letters", which will appear in print on Friday, Aug. 29.

Basic understanding after 30 years

With their research results the Bochum Electrical Engineers Dr. Thomas Mussenbrock and Prof. Ralf Peter Brinkmann (Institute for Theoretical Electrical Engineering at the Ruhr University of Bochum) together with colleagues from the University of California at Berkeley surrounding Prof. Mike Lieberman have contributed to basic understanding of so-called low temperature plasma, which has already been in industrial use for over 30 years. “Since the nineteen seventies vigorous technical debates have been in progress regarding the function of plasma, which, however, have not led to any conclusive results. In particular, we do not fully understand the exact energy coupling mechanism“, stated Thomas Mussenbrock. “Ever since plasma has been discovered and utilized, significant differences have existed between theoretical predictions on the behavior of the plasma and actual measurements.” The mechanism now discovered at the Ruhr University provides a new approach for explaining the heating mechanisms in low temperature plasma for the first time.

Versatile types of plasma

Without plasma, no Pentium: For example electrically excited gases can be used to form the structures on microchips by removing or depositing materials in the nanometer range. Today plasma-based processes already account for nearly one-half of all processing steps in the field of microelectronics. But plasma technology is not only essential here; it is also used in lighting, environmental and medical engineering. One of the particular characteristics of the low temperature plasmas used is the number of electrons contained with temperatures of over 10,000 degrees Celsius – in contrast to ions present as well as neutral atoms and molecules, which are comparatively cold at virtually room temperature . This thermal non-equilibrium is what initiates chemical reactions and other processes, making low temperature plasmas so versatile.

Key to specific utilization

The question of why the electrons could become so hot particularly at very low gas pressures, was not clarified completely up to this time. Researchers at CPST have now been successful in proving this “non-linear electron resonance heating” theoretically and experimentally. The basis of this mechanism is the intrinsic tendency of the plasma to oscillate. Excitation of a certain oscillation – starting from non-linear behavior of the plasma boundary sheath – causes a “self-excitation” of the oscillation in the electrical current flowing in the plasma. Theoretical studies have shown that non-linear electron resonance heating can more than double the efficiency of the energy coupling. Laboratory tests at CPST by Prof. Uwe Czarnetzki (Department of Physics and Astronomy) and Prof. Peter Awakowicz (Department of Electrical Engineering and Information Technology) have confirmed this result. The RUB researchers have simultaneously provided a new approach to understanding how plasma can be excited electrically for maximum efficiency. “Electron resonance can even be controlled specifically to initiate the mechanism”, according to Thomas Mussenbrock.

Dr. Thomas Mussenbrock | alfa
Further information:
http://www.tet.rub.de
http://www.rub.de

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>