Lifeboat Foundation

The research team of Assistant Professor Masahiko Sato and Professor Yasushi Todo of the National Institutes of Natural Sciences (NINS) National Institute for Fusion Science (NIFS) has succeeded using computer simulation in reproducing the high-pressure plasma confinement observed in the Large Helical Device (LHD). This result has enabled highly accurate predictions of plasma behavior aimed at realizing an economical helical fusion reactor.

In order to realize fusion energy, we must confine high pressure plasma using the magnetic field for a long duration. Although higher pressure plasma can be confined by a stronger magnetic field, it costs more to generate a stronger magnetic field using electromagnetic coils. Therefore, if the magnetic field strength is the same, a device that can confine higher pressure plasma is economically desirable. Because the LHD has succeeded in maintaining high-pressure plasma, there is great expectation in realizing a helical fusion reactor.

Design research for a future fusion reactor is performed based on computer simulations predicting the behavior of magnetically confined plasma. We require highly accurate simulations. To confirm the accuracy, the simulations are required to reproduce the experimental results obtained by the existing devices. However, the simulations had not reproduced the experimental results obtained by the LHD showing that high-pressure plasma is maintained. This has been a serious problem for the design research for an economical helical fusion reactor.

One of the world’s largest petawatt laser facility, LFEX, located in the Institute of Laser Engineering at Osaka University. Credit: Osaka University.

Laser Engineering at Osaka University have successfully used short, but extremely powerful laser blasts to generate magnetic field reconnection inside a plasma. This work may lead to a more complete theory of X-ray emission from astronomical objects like black holes.

In addition to being subjected to extreme gravitational forces, matter being devoured by a black hole can be also be pummeled by intense heat and magnetic fields. Plasmas, a fourth state of matter hotter than solids, liquids, or gasses, are made of electrically charged protons and electrons that have too much energy to form neutral atoms. Instead, they bounce frantically in response to magnetic fields. Within a plasma, magnetic reconnection is a process in which twisted magnetic field lines suddenly “snap” and cancel each other, resulting in the rapid conversion of magnetic energy into particle kinetic energy. In stars, including our sun, reconnection is responsible for much of the coronal activity, such as solar flares. Owing to the strong acceleration, the charged particles in the black hole’s accretion disk emit their own light, usually in the X-ray region of the spectrum.

A tabletop gravity wave detector powered by a nanoscopic diamond could revolutionize particle physics, its creators say. And unlike existing detectors, it fits on a tabletop.

In a preprint paper, researchers describe a small device with the modified diamond in the center. The diamond is prepared by trading one carbon for one nitrogen, which opens a critical electron gap where a new and functional electron is inserted.

Like a comic book come to life, researchers at Stanford University have developed a kind of X-ray vision—only without the X-rays. Working with hardware similar to what enables autonomous cars to “see” the world around them, the researchers enhanced their system with a highly efficient algorithm that can reconstruct three-dimensional hidden scenes based on the movement of individual particles of light, or photons. In tests, detailed in a paper published Sept. 9 in Nature Communications, their system successfully reconstructed shapes obscured by 1-inch-thick foam. To the human eye, it’s like seeing through walls.

“A lot of imaging techniques make images look a little bit better, a little bit less noisy, but this is really something where we make the invisible visible,” said Gordon Wetzstein, assistant professor of electrical engineering at Stanford and senior author of the paper. “This is really pushing the frontier of what may be possible with any kind of sensing system. It’s like superhuman vision.”

This technique complements other vision systems that can see through barriers on the microscopic scale —for applications in medicine—because it’s more focused on large-scale situations, such as navigating self-driving cars in fog or heavy rain and satellite imaging of the surface of Earth and other planets through hazy atmosphere.

Future wireless networks of the 6th generation (6G) will consist of a multitude of small radio cells that need to be connected by broadband communication links. In this context, wireless transmission at THz frequencies represents a particularly attractive and flexible solution. Researchers at Karlsruhe Institute of Technology (KIT) have now developed a novel concept for low-cost terahertz receivers that consist of a single diode in combination with a dedicated signal processing technique. In a proof-of-concept experiment, the team demonstrated transmission at a data rate of 115 Gbit/s and a carrier frequency of 0.3 THz over a distance of 110 meters. The results are reported in Nature Photonics.

5G will be followed by 6G: The sixth generation of mobile communications promises even higher data rates, shorter latency, and strongly increased densities of terminal devices, while exploiting Artificial Intelligence (AI) to control devices or autonomous vehicles in the Internet-of-Things era. “To simultaneously serve as many users as possible and to transmit data at utmost speed, future wireless networks will consist of a large number of small radio cells,” explains Professor Christian Koos, who works on 6G technologies at KIT together with his colleague Professor Sebastian Randel. In these radio cells, distances are short such that high data rates can be transmitted with minimum energy consumption and low electromagnetic immission. The associated base stations will be compact and can easily be mounted to building facades or street lights.

To form a powerful and flexible network, these base stations need to be connected by high-speed wireless links that offer data rates of tens or even hundreds of gigabits per second (Gbit/s). This may be accomplished by terahertz carrier waves, which occupy the frequency range between microwaves and infrared light waves. However, terahertz receivers are still rather complex and expensive and often represent the bandwidht bottleneck of the entire link. In cooperation with Virginia Diodes (VDI) in Charlottesville, U.S., researchers of KIT’s Institute of Photonics and Quantum Electronics (IPQ), Institute of Microstructure Technology (IMT), and Institute for Beam Physics and Technology (IBPT) have now demonstrated a particularly simple inexpensive receiver for terahertz signals. The concept is presented in Nature Photonics.

Emerging quantum materials can be defined by topology and strong electron correlations, although their applications in experimental systems are relatively limited. Weyl semimetals incorporating magnetism offer a unique and fertile platform to explore emerging phenomena in developing topological matter and topological spintronics. The triangular antiferromagnet Mn₃Sn exhibits many exotic physical properties as an antiferromagnetic (AFM) Weyl semimetal (WSM), including an attractively large spontaneous Hall effect.

The spontaneous Hall effect was discovered more than a century ago and understood in terms of time-reversal symmetry breaking by the internal spin structure of antiferromagnetic, ferromagnetic or skyrmionic (small swirling topological defects in the magnetization) forms.

In a new report now published on Science Advances, Durga Khadka and a team of scientists in physics, materials science, neutron research and engineering in the U.S. reported the synthesis of epitaxial Mn_3+x Sn_1−x films with compositions similar to bulk samples. When they replaced the tin (Sn) atoms with magnetic manganese (Mn) atoms in the samples, they noted the Kondo effect; a celebrated example of strong correlations to emerge, then develop coherence and induce a hybridization energy gap. The process of magnetic doping and gap opening facilitated rich extraordinary properties for the new materials.

Fusion Science and Technology: Vol. 75, No. 3, pp. 208–217.

A pair of Danish computer scientists have solved a longstanding mathematics puzzle that lay dormant for decades, after researchers failed to make substantial progress on it since the 1990s.

The abstract problem in question is part of what’s called graph theory, and specifically concerns the challenge of finding an algorithm to resolve the planarity of a dynamic graph. That might sound a bit daunting, so if your graph theory is a little rusty, there’s a much more fun and accessible way of thinking about the same inherent ideas.

Going as far back as 1913 – although the mathematical concepts can probably be traced back much further – a puzzle called the three utilities problem was published.

Salk study is the first to reveal ways cells from the human circulatory system change with age and age-related diseases.

Salk scientists have used skin cells called fibroblasts from young and old patients to successfully create blood vessels cells that retain their molecular markers of age. The team’s approach, described in the journal eLife on September 8, 2020, revealed clues as to why blood vessels tend to become leaky and hardened with aging, and lets researchers identify new molecular targets to potentially slow aging in vascular cells.

“The vasculature is extremely important for aging but its impact has been underestimated because it has been difficult to study how these cells age,” says Martin Hetzer, the paper’s senior author and Salk’s vice president and chief science officer.