During downtimes when the reactor is offline, as it is right now, engineers make upgrades that will help them achieve their goal of making fusion a viable energy source--a long-standing mission that will likely continue for decades.
MIT's reactor, known as Alcator C-Mod, is one of several tokamak plasma discharge reactors in the world. Inside the reactor, magnetic fields control the superheated plasma (up to 50 million degrees Kelvin) as it flows around the tube.
Fusion occurs when two deuterons, or one deuteron and one triton--nuclei of heavy hydrogen--fuse, creating helium and releasing energy. The reactions can only occur at extremely high temperatures.
Although MIT's reactor is smaller than others, it has a stronger magnetic field than some larger reactors, allowing the plasma to become denser at comparable temperatures. "That positions us to provide important data you can't get anywhere else," said Earl Marmar, head of MIT's Alcator C-Mod project and senior research scientist in the Department of Physics.
One major goal of the upgrades is to create a system where plasma can flow in a steady state, rather than short pulses, or bursts.
Last year, engineers added a microwave generator that creates phased waves that flow around the ring, reinforcing the plasma current. The microwaves interact with the highest velocity electrons in the plasma, pushing them around the ring.
"It's possible to use this approach to go to fully steady-state plasma," Marmar said. "As an attractive energy source, ultimately we want steady state."
Benefits of a steady-state system include a constant energy output, less need for energy storage and less stress on the system, he said.
This year's modifications include the installation of a cryopump, which will allow scientists to control the density of the plasma over a long period of time--another necessary step to achieving a steady-state flow.
Several other modifications will allow the researchers to more accurately measure properties of the plasma, such as density and temperature. The new devices will also allow them to more accurately detect and measure magnetic and electric fields generated by the plasma.
The reactor, which has been offline for upgrades since August, is expected to be ready to use again starting in March.
More than 100 MIT researchers from the Departments of Physics, Nuclear Science and Engineering, and Electrical Engineering and Computer Science, including about 30 graduate students, use the Alcator C-Mod reactor to run experiments.
On a recent morning, the control room, normally packed with scientists at about 100 computer monitors, was nearly empty while engineers, scientists and students worked on modifications to the reactor, located in the next room.
When experiments are going on, researchers from around the world can participate in and watch the proceedings through the Internet.
There is high demand for time to run experiments on the reactor, but priority is given to projects that have high relevance to the Alcator goals and also to MIT graduate student research projects.
"One of our highest priorities is to get graduate students the run time they need," Marmar said.
For more information on the Alcator project, visit www.psfc.mit.edu/research/alcator/.
Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts
08.12.2016 | Institut für Solarenergieforschung GmbH
Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
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...
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...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine