Physicist Fatima Ebrahimi at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) has published a paper showing that magnetic reconnection -- the process in which magnetic field lines snap together and release energy -- can be triggered by motion in nearby magnetic fields. By running computer simulations, Ebrahimi gathered evidence indicating that the wiggling of atomic particles and magnetic fields within electrically charged gas known as plasma can spark the onset of reconnection, a process that, when it occurs on the sun, can spew plasma into space.
That plasma can eventually interact with magnetic fields surrounding the Earth, endangering communications networks and power systems. In fusion facilities, reconnection can help start and confine the plasma that fuels fusion reactions. This research was funded by the DOE's Office of Science (Fusion Energy Sciences) and was published in the December issue of Physics of Plasmas.
Using a computer code developed by researchers at universities and fusion labs, Ebrahimi simulated plasma circulating within a vessel shaped like a doughnut. The vessel mimicked the doughnut shape of fusion facilities called tokamaks. The simulated facility had an opening in its floor for physicists to inject magnetic field lines that would balloon in the tokamak's interior and initiate the fusion process.
Reconnection occurred in the following way. The field lines forming the balloon created an electric current that produced three-dimensional wiggles and wobbles that pushed the open end of the balloon until it closed. At that point, magnetic reconnection occurred and turned the magnetic balloon into a magnetic bubble called a plasmoid that carries electric current.
Ebrahimi is now expanding that research. She is currently looking into how to harness the current to create and confine a fusion plasma without using a large central magnet called a solenoid.
Different conditions can set off the reconnection process. "If the strength of the field lines associated with the original magnetic balloon is not enough on its own to instigate reconnection," Ebrahimi said, "the secondary magnetic wiggles can amplify the magnetic fields at the reconnection site, triggering the event." She is also investigating the amplification of magnetic fields through these secondary three-dimensional magnetic and fluid wiggles known as the dynamo effect.
These findings on the effect of magnetic fields can have a broad impact. "The analysis and the modeling can help us better understand how the reconnection process that is triggered by magnetic perturbations in plasmas can lead to the detachment of magnetic loops on the surface of the sun, or efficient startup for fusion plasmas," Ebrahimi said.
PPPL, on Princeton University's Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas -- ultra-hot, charged gases -- and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy's Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Raphael Rosen | EurekAlert!
Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland
On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Life Sciences
24.04.2018 | Materials Sciences
24.04.2018 | Trade Fair News