Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016

News from the 58th Annual Meeting of the APS Division of Plasma Physics

Researchers at General Atomics (GA) have invented a new kind of gamma ray camera that can image beams of energetic electrons inside ultra-hot fusion plasma.


Each pixel of the camera is an individual detector pictured above. These are arranged to look into the plasma and focus on the hottest part of the plasma.

Credit: General Atomics

The device is used in ongoing global research that is developing fusion into a new clean energy source. Turning fusion fuel into extractable energy requires it to be hotter than the center of the sun, hence in the plasma state. If the shutdown phase of operation is not controlled well, released magnetic energy can drive a population of electrons to relativistic speeds. If this population is not controlled, the electrons impact the inner walls of the plasma chamber, leading to material damage.

A team of researchers is working to better understand the properties of these electrons at the DIII-D National Fusion Facility operated by GA in San Diego for the U.S. Department of Energy. They designed and built a Gamma Ray Imager to capture the image of these particles.

The Gamma Ray Imager works on the principle of a standard pinhole camera (Figure 1), except that it is made of lead and weighs 420 pounds (190.5 kilograms). The imager actually records images of equally energetic gamma rays that are emitted by the electrons, and the lead is necessary to achieve a good focus (Figure 2). These gamma ray measurements provide information about the energy, direction, and quantity of electrons in the relativistic population, giving researchers an unparalleled view of how the energetic electrons evolve and interact with the fusion plasma.

"This system allows us to see with unprecedented detail how different plasma properties can mitigate these electrons," said Dr. Carlos Paz-Soldan, the scientist who led the first experiments utilizing the new camera. The results, to be presented at the American Physical Society Division of Plasma Physics conference Oct. 31-Nov. 4, demonstrate experimentally that radiation "reaction" forces are able to sap the highest energy electrons while collisions with other electrons are most effective at low energy (Figure 3).

These measurements imply that energetic electron control is not one-size-fits all, and that different energies require different control strategies.

With the new measurements, scientists can compare the behavior of the electron populations to theoretical models being developed by research teams worldwide. These models are, in turn, crucial to predict how the electron populations will behave in new reactors, such as the ITER tokamak now under construction in Cadarache, France, and thus ensure they can be adequately controlled.

###

Contact:

Dr. Carlos Paz-Soldan
General Atomics
paz-soldan@fusion.gat.com

Abstract CO4.00010


Synchrotron and collisional damping effects on runaway electron distributions
2:00 PM-5:00 PM, Monday, October 31, 2016, Room: 230 A

Media Contact

James R Riordon
riordon@aps.org
301-209-3238

 @APSphysics

http://www.aps.org 

James R Riordon | EurekAlert!

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>