Magnetic confinement fusion has the potential to provide a substantial proportion of the world’s energy needs in the 21st century in a safe and environmentally friendly way. Its realisation is, however, hampered by the complex behavior of hot collisionless plasmas (ion gases) in strong magnetic fields. Such plasmas are subject to temperature and density gradient driven microturbulence which leads to particle and heat losses and tends to keep the plasma from reaching a "burning" state.
Simulations are necessary if we are to understand and control plasma microturbulence. However, because fusion plasmas are virtually collisionless, a three-dimensional (i.e., in space) fluid description must, in principle, be abandoned, in favor of a six-dimensional (i.e., in phase space) kinetic one.
Fortunately, several processes on very small spatio-temporal scales – such as the gyrating motion of the particles around magnetic field lines – can be removed, analytically, from the basic equations, thus making the problem five-dimensional. This reduces the computational requirements by many orders of magnitude, without sacrificing accuracy. This approach is called gyrokinetics, which gave the present project its name.
The GYROKINETICS project was carried out in 2006 and 2007 by researchers from the Max Planck Institute for Plasma Physics at Garching, Germany, and the Ecole Polytechnique Fédérale of Lausanne, in Switzerland using DEISA’s resources under the DECI and the JRA3 frameworks.
As a result, the research group were able to show that certain small-scale turbulent processes can make substantial contributions to the overall heat transport carried by the plasma electrons. It turned out, in particular, that there often tends to be a scale separation between ion and electron thermal transport. While the former is usually carried more or less exclusively by long wavelength fluctuations, a substantial proportion of the latter can be carried by much smaller scales.
These findings represent an important new insight into the physics of turbulent transport in magnetized plasmas, and will have important implications for future full-torus simulations of large fusion devices, such as the International Thermonuclear Experimental Reactor ITER.
Kirsti Turtiainen | alfa
Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen
New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences
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...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy