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 Optical Nanoscope Allows Imaging of Quantum Dots
23.01.2018 | Universität Basel

nachricht Two dimensional circuit with magnetic quasi-particles
22.01.2018 | Technische Universität Kaiserslautern

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: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | 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

 
Latest News

Researchers reveal how microbes cope in phosphorus-deficient tropical soil

23.01.2018 | Earth Sciences

Opening the cavity floodgates

23.01.2018 | Life Sciences

Siberian scientists suggested a new method for synthesizing a promising magnetic material

23.01.2018 | Materials Sciences

VideoLinks Science & Research
Overview of more VideoLinks >>>