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An artist’s conception of an exoplanetary system, in this case around the star HD7924, that hosts two super-Earths (objects c and d in the image). Astronomers have discovered a star with three super-Earths that transit, making them prime candidates for detailed atmospheric studies. Karen Te industrial networking  ramura & BJ Fulton, UH IfA

Over 3500 extra-solar planets have been confirmed to date. Most of them were discovered using the transit method, and astronomers can combine the transit light curves with velocity wobble observations to determine the planet’s mass and radius, and thereby constrain its interior structure. The atmosphere can also be studied in a transit by using the fact that the chemical composition of the atmosphere means its opacity varies with wavelength. By measuring the depth of the transit at different wavelengths, it is possible to infer the composition and temperature of the planet’s atmosphere.

CfA astronomers Joseph Rodriguez, Andrew Vanderburg, Jason Eastman, David Latham, and Samuel Quinn and their team of scientists discovered three small transiting planets orbiting the star GJ9827 which lies at the relatively close distance of 100 light-years. The three exoplanets have radii of about 1.6, 1.3, and 2.1 Earth-radii respectively. All of them are categorized as super-Earths, that is, with masses that are larger than Earth’s but less than Neptune’s. (Radial velocity measurements of the exoplanets, not included in this paper, have just been separately published and confirm this conclusion.)

GJ9827 is one of the few known s vending vms tars to have multiple transiting terrestrial-sized exoplanets that are suited for atmospheric characterization. In fact, its three exoplanets are particularly interesting because two of them have radii between 1.5 and 2.0 Earth-radii. Across this range in radii, the composition of planets is expected to change from rocky to gaseous; moreover, there are relatively few such candidates for study. These planets orbit very close to the star, with periods of 1.2, 3.6 and 6.2 days respectively, and at these close distances they have fairly hot temperatures, estimated at 1172, 811 and 680 degrees kelvin. Future observations will probe their atmospheres and provide a much more detailed picture of this unusual family of super-Earths.

Publication: Joseph E. Rodriguez, et al., “A System of Three S industrial wireless router  uper Earths Transiting the Late K-Dwarf GJ 9827 at 30 pc,” AJ 155, 72, 2018; doi:10.3847/1538-3881/aaa292

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Frequency measurements from 2015 (data: 50Hertz): the power grid frequency fluctuates around 50 Hz in the European grid and exhibits large jumps particularly in the trading intervals of 15 minutes. Usually, the grid frequency is within the yellow area but upward and downward deviations (grey) are particularly likely every 15 minutes. MPI für Dynamik und Selbstorganisation / Benjamin Schäfer

Our power grid fault location  grid works at a frequency of 50 hertz – usually generated by tur retail  bines, for example in hydro- or coal power plants, which rotate at a speed of 50 revolutions per second. “When a consumer uses more electrical energy from the power grid, the grid frequency drops slightly before an increased energy feed-in re-establishes the original frequency,” explains Benjamin Schaefer from the Max Planck Institute for Dynamics and Self-Organization (MPIDS) in Goettingen and lead author of the study. “Deviations from the nominal value of 50 hertz must be kept to a minimum, as otherwise sensitive electrical devices could be damaged.”

Renewable energy generation also causes grid frequency fluctuations because the wind does not always blow at the same speed and clouds constantly alter the feed-in from photovoltaic systems. A frequent suggestion for integrating renewable energy generators into the power grid involves breaking the grid down into small autonomous cells known as microgrids. This would allow a community with a combined heat and power unit and its own wind and photovoltaic generators, for example, to operate its energy systems in an autonomous manner.

But what impact would this division into small cells and additional renewable ge light industrial  nerators have on the power grid? To answer this question, scientists from Forschungszentrum Juelich and MPIDS analysed the grid frequency fluctuations in power grids in different regions of the world – and using mathematical models, they predicted potential vulnerabilities and their causes.

Two surprises in one analysis

Firstly, they collated measurements from Europe, Japan, and the USA. Then, they systematically analysed the data and were surprised on two accounts. “The first surprise was that the grid showed particularly strong fluctuations every 15 minutes,” says Dirk Witthaut from Juelich’s Institute of Energy and Climate Research und the Institute for Theoretical Physics of the University of Cologne. “This is the exact time frame during which generators on the European electricity market agree on a new distribution for the electricity generated – this alters how much electricity is fed into the grid, and where. In Europe at least, power trading therefore plays a key role in balancing grid frequency fluctuations.”

The second surprise was that statistical grid fluctuations around the nominal value of 50 hertz do not follow the expected Gaussian distribution, which is a symmetrical distribution around an expected value. Instead, more extreme fluctuations are probable. Using mathematical models, the scientists calculated the expected fluctuations depending on the grid size and estimated the degree to which the fluctuations depended on renewables.

Power trading as a key factor

A comparison of the investigated regions showed that a large proportion of renewables did indeed lead to greater grid fluctuations. “For example, the share of wind and solar generation in the United Kingdom is much higher than in the USA, leading to greater fluctuations in grid frequency,” explains Dirk Witthaut. For an increased share of renewables, the scientists therefore recommend increased investment in an intelligent adjustment of generator and consumer according to the grid frequency – known as primary control and demand control.

One of the most interesting findings of the study, however, is that grid frequency fluctuation caused by power trading appeared to be more significant than fluctuation caused by renewable feed-in.

The scientists also discovered that small power grids show larger fluctuations. “Our study indicates that dividing large and thus very slow grids – such as the synchronous grid of Continental Europe – into microgrids will cause larger frequency fluctuations,” says Benjamin Schaefer. “Technically, microgrids are therefore only an option if today’s very stringent frequency standards were to be relaxed.”

Publication: Benjamin Schäfer, et al., “Non-Gaussian power grid frequency fluctuations characterized by Lévy-stable laws and superstatistics,” Nature Energy (2018) doi:10.1038/s41560-017-0058-z

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A graduated cylinder model of the ocean. The green shows cyanobacteria and the brown shows the oxidized iron.

A new experiment by Elizabeth Swanner evaluating the reduction of iron in prehistoric oceans may reinterpret the conditions un Industrial VPN router der which iron-rich sedimentary rock is formed.

Swanner, assistant professor of geological and atmosphsmart vending machineeric sciences, was part of an internationally collaborative research team including researchers from the University of Tuebingen, Germany and the Chinese Academy of Sciences in Beijing, China. The team modeled the prehistoric ocean, similar to that of the Archean Era 2.5 billion years ago within a graduated cylinder.

“We really only wanted to simulate it in the vertical dimension, so we used a graduated cylinder and modified it,” Swanner said.

In a previous experiment the researchers had modified the cylinder to simulate an Archean ocean with large amounts of iron and no oxygen except for what was made by cyanobacteria. Ports along the cylinder’s side allowed for sampl Dual SIM M2M router  ing at various levels.

(a) Schematic cross-section and dimensions of the column. Small darker grey squares are optodes, labeled with the depth in the column. Dark grey sampling ports show the arrangement of fixed needles used to take aqueous samples at different depths in the center of the column. White ports show where medium was pumped in (bottom), pumped out (top), and an additional port used for flushing the headspace. (b) Schematic cross-section of a Precambrian continental margin overlying a deep, ferruginous basin, simulated in one dimension (vertically) by the column experiment. Insets show that oxic Fe(III) reduction described here could take place in the water column and/or in a benthic setting, simulated by glass beads in the column.Elizabeth D. Swanner, et al., Scientific Reports, volume 8, Article number: 4238 (2018) doi:10.1038/s41598-018-22694-y

“We were studying cyanobacteria because these are the organisms which we think put all of the oxygen in the atmosphere originally,” she said.

The research, published by Scientific Reports, showed that despite the oxygenation by the cyanobacteria, much of the iron did not remain oxidized but was reduced again into its dissolved form.

This unexpected result may be explained by an enzyme on cyanobacteria which reduces iron. In the modern ocean, which contains at least 1000 times less iron, cyanobacteria reduce a small amount of iron, but the experiment showed a larger amount of iron reduction than the researchers anticipated. Another possible explanation is that the iron is reduced by a photochemical reaction occurring when the iron is hit by light.

The implications of this finding could change the conditions under which iron-rich sedimentary rocks are thought to be formed from the ancient oceans.

“Traditionally if you see iron enriched in sediments from the ocean you tend to think it was deposited under anoxic conditions,” Swanner said. “But potentially we have a way to still deposit a lot of iron but have it be deposited under fully oxygenated conditions.”

The initial results in the laboratory prompt new questions for Swanner, including whether she will find evidence of this process in the Midwestern lakes that her research group is now studying. These lakes have iron at the bottom and oxygen only in the top of the water column, and also contain cyanobacteria.

Publication: Elizabeth D. Swanner, et al., “Oxic Fe(III) reduction could have generated Fe(II) in the photic zone of Precambrian seawater,” Scientific Reports, volume 8, Article number: 4238 (2018) doi:10.1038/s41598-018-22694-y

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Giant perturbations called hot flow anomalies in the solar wind near Venus can pull the upper layers of its atmosphere, the ionosphere, up and away from the surface of the planet. Image Credit: NASA

Using data from the European Space Agency’s Venus Express, astronomers have discovered planet-sized space weather explosions at Venus.

Researchers recently discovered that a common space weather phenomenon on the outskirts of Earth’s magnetic bubble, the magneto industrial wireless modem  sphere, has much lar remote secure networking  ger repercussions for Venus. The giant explosions, called hot flow anomalies, can be so large at Venus that they’re bigger than the entire planet and they can happen multiple times a day.

“Not only are they gigantic,” said Glyn Collinson, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But as Venus doesn’t have a magnetic field to protect itself, the hot flow anomalies happen right on top of the planet. They could swallow the planet whole.”

Collinson is the first author of a paper on these results that appeared online in the Journal of Geophysical Research in February 2014. The work is based on observations from the European Space Agency’s Venus Express. The results show just how large and how frequent this kind of space weather is at Venus.

Earth is protected from the constant streaming solar wind of radiation by its magnetosphere. Venus, however, has no such luck. A barren, inhospitable planet, with an atmosphere so dense that spacecraft landing there are crushed within hours, Venus has no magnetic protection.

Scientists like to compare the two: What happened differently at Earth to make it into the life-supporting planet it is today? What would Earth be like without its magnetic field?

At Earth, hot flow anomalies do not make it inside the magnetosphere, but they release so much energy just outside that the solar wind is deflected, and can be forced to move back toward the sun. Without a magnetosphere, what happens at Venus is very different.

Venus’s only protec Wireless ATM  tion from the solar wind is the charged outer layer of its atmosphere called the ionosphere. A sensitive pressure balance exists between the ionosphere and the solar wind, a balance easily disrupted by the giant energy rush of a hot flow anomaly. The hot flow anomalies may create dramatic, planet-scale disruptions, possibly sucking the ionosphere up and away from the surface of the planet.

Publication: G. A. Collinson, et al., “A survey of hot flow anomalies at Venus,” Journal of Geophysical Research: Space Physics, 2014; DOI: 10.1002/2013JA018863

Image: NASA

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The Aurora Borealis viewed by the crew of Expedition 30 on board the International Space Station. The sequence of shots was taken on February 7, 2012 from 09:54:04 to 10:03:59 GMT, on a pass from the North Pacific Ocean, west of Canada, to southwestern Illinois.

New research from scientists at NASA’s Jet Propulsion Laboratory and at the University of New Brunswick looks at irregularities in the ionosphere, comparing turbulence in the auroral region to that at higher latitudes.

When you don’t know how to get to an unfamiliar place, you probably rely on a smart phone or other device with a Global Positioning System (GPS) module for guidance. You may not realize that, especially at high latitudes on our planet, signals traveling between G vending computer PS satellites and your device can get distorted in Earth’s upper atmosphere.

Researchers at NASA’s Jet Propulsion Laboratory, Pasadena, California, in collaboration with the University of New Brunswick in Canada, are studying irregularities in the ionosphere, a part of the atmosphere centered about 217 miles (350 kilometers) above the ground that defines the boundary between Earth and space. The ionosphere is a shell of charged particles (electrons and ions), called plasma, that is produced by solar radiation and energetic particle impact.

The new study, published in the journal Geophysical Research Letters, compares turbulence in the auroral region to that at higher latitudes, and gains insights that could have implicatiobest industrial wifi routerns for the mitigation of disturbances in the ionosphere. Auroras are spectacular multicolored lights in the sky that mainly occur when energetic particles driven from the magnetosphere, the protective magnetic bubble that surrounds Earth, crash into the ionosphere below it. The auroral zones are narrow oval-shaped bands over high latitudes outside the polar caps, which are regions around Earth’s magnetic poles. This study focused on the atmosphere above the Northern Hemisphere.

“We want to explore the near-Earth plasma and find out how big plasma irregularities need to be to interfere with navigation signals broadcast by GPS,” said Esayas Shume. Shume is a researcher at JPL and the California Institute of Technology in Pasadena, and lead author of the study.

If you think of the ionosphere as a fluid, the irregularities comprise regions of lower density (bubbles) in the neighborhood of high-density ionization areas, creating the effect of clumps of more and less intense ionization. This “froth” can interfere with radio signals including those from GPS and aircraft, particularly at high latitudes.

The size of the irregularities in the plasma gives researchers clues about their cause, which help predict when and where they will occur. More turbulence means a bigger disturbance to radio signals.

“One of the key findings is that there are different kinds of irregularities in the auroral zone compared to the polar cap,” said Anthony Mannucci, supervisor of the ionospheric and atmospheric remote sensing group at JPL. “We found that the effects on radio signals will be different in these two locations.”

The researchers found that abnormalities above the Arctic polar cap are of a smaller scale – about 0.62 to 5 miles (1 to 8 kilometers) – than in the auroral region, where they are 0.62 to 25 miles (1 to 40 kilometers) in diameter.

Why the difference? As Shume explains, the polar cap is connected to solar wind particles and electric fields in interplanetary space. On the other hand, the region of auroras is connected to the energetic particles in Earth’s magnetosphere, in which magnetic field lines close around Earth. These are crucial details that explain the different dynamics of the two regions.

To look at irregularities in the ionosphere, researchers used data from the Canadian Space Agency satellite Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE), which launched in September 2013. The satellite covers the entire region of high latitudes, making it a useful tool for exploring the ionosphere.

The data come from one of the instruments on CASSIOPE that looks at GPS signals as they skim the ionosphere. The instrument was conceived by researchers at the University of New Brunswick.

“It’s the first time this kind of imaging has been done from space,” said Attila Komjathy, JPL principal investigator and co-author of the study. “No one has observed these dimensional scales of the ionosphere before.”

The research has numerous applications. For instance, aircraft flying over the North Pole rely on solid communications with the ground; if they lose these signals, they may be required to change their flight paths, Mannucci said. Radio telescopes may also experience distortion from the ionosphere; understanding the effects could lead to more accurate measurements for astronomy.

“It causes a lot of economic impact when these irregularit Industrial 3G Router  ies flare up and get bigger,” he said.

NASA’s Deep Space Network, which tracks and communicates with spacecraft, is affected by the ionosphere. Komjathy and colleagues also work on mitigating and correcting for these distortions for the DSN. They can use GPS to measure the delay in signals caused by the ionosphere and then relay that information to spacecraft navigators who are using the DSN’s tracking data.

“By understanding the magnitude of the interference, spacecraft navigators can subtract the distortion from the ionosphere to get more accurate spacecraft locations,” Mannucci said.

Other authors on the study were Richard B. Langley of the Geodetic Research Laboratory, University of New Brunswick, Fredericton, New Brunswick, Canada; and Olga Verkhoglyadova and Mark D. Butala of JPL. Funding for the research came from NASA’s Science Mission Directorate in Washington. JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA.

Publication: E. B. Shume, et al., “Intermediate-scale plasma irregularities in the polar ionosphere inferred from GPS radio occultation,” Geophysical Research Letters, 2015; DOI: 10.1002/2014GL062558

Image: NASA/JSC

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Deep below the ocean’s surface, huge eddies are often formed. The depths have their own kinds of weather systems. NASA’s Terra satellite captured this photo of a gigantic plankton-fueled eddy that was released. The eddy is completely submerged under water.

Unlike terrestrial storms, ocean whirlwinds draw nutrients from the deep, nourishing blooms of microscopic marine life in the otherwise somewhat barren open ocean, fertilizing the surface waters. Eddies spin off from major ocean current system and can l cashless vending  ast for months. Researchers think that this 93-mile wide anti-cyclonic eddy peeled off the Agulhas current, which flows along the south-eastern coast of Africa to the tip of South Africa. Agulhas eddies or current rings tend to be the largest in the world.

This edd VPN gateway   remote connectivity  y is visible from space, and because of its life-giving properties, it’s slightly bluer than the surrounding water, thanks to the blooming plankton it contains. The swirls have been measured up to 150 kilometers (93 miles).

The natural-color images of the deep-ocean eddy were captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, 800 km south of South Africa.

The huge masses of spinning water in whirlpool patterns can rotate either clockwise or counterclockwise, and can stretch for hundreds of miles, lasting months.

[via New Scientist, images by NASA and Wikipedia]

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This simulation depicts two electron bunches – containing 5 billion to 6 billion electrons each – that were accelerated by a laser-generated column of plasma inside an oven of hot lithium gas during experiments at SLAC. (SLAC National Accelerator Laboratory)

Researchers hit a milestone in demonstrating the practicality of plasma wakefield acceleration, boosting bunches of electrons to energies 400 to 500 times higher than they could reach traveling the same distance in a conventional accelerator.

Menlo Park, California — Scientists from the Department of Energy’s SLAC National Accelerator Laboratory and the University of California, Los Angeles have shown that a promising technique for accelerating electrons on waves of plasma is efficient enough to power a new generation of shorter, more economical accelerators. This could greatly expand their use in areas such as medicine, national security, industry and high-energy physics research.

This achievement is a milestone in demonstrating the practicality of plasma wakefield acceleration, a technique in which electrons gain energy by essentially surfing on a wave of electrons within an ionized gas.

Using SLAC’s Facility for Advanced Accelerator Experimental Tests (FACET), a DOE Office of Science User Facility, the researchers boosted bunches of electrons to energies 400 to 500 times higher than they could reach traveling the same distance in a conventional accelerator. Just as important, energy was transferred to the electrons much more efficiently than in previous experiments. This crucial combination of energy and efficiency had never been reached before. The results are described in a paper published today in the journal Nature.

“Many of the practical aspects of an accelerator are determined by how quickly the particles can be accelerated,” said SLAC accelerator physicist Mike Litos, lead author of the paper. “To put these results in context, we have now shown that we could use this technique to accelerate an electron beam to the same energies achieved in the 2-mile-long SLAC linear accelerator in less than 20 feet.”

Plasma wakefields have been of interest to accelerator physicists for 35 years as one of the more promising ways to drive the smaller, cheaper accelerators of the future. The UCLA and SLAC groups have been at the forefront of research on plasma wakefield acceleration for more than a decade. In a 2007 paper, researchers announced they’d accelerated electrons in the tail end of a long electron bunch from 42 billion electronvolts to 85 billion electronvolts, causing a great deal of excitement in the scientific community. However, fewer than 1 billion of the 18 billion electrons in the pulse actually gained energy and they had a wide spread of energies, making them unsuitable for experiments.

In this experiment, researchers sent pairs of electron bunches containing 5 billion to 6 billion electrons each into a laser-generated column of plasma inside an oven of hot lithium gas. The first bunch in each pair was the drive bunch; it blasted all the free electrons away from the lithium atoms, leaving the positively charged lithium nuclei behind – a configuration known as the “blowout regime.” The blasted electrons then fell back in behind the second bunch of electrons, known as the trailing bunch, forming a “plasma wake” that propelled the trailing bunch to higher energy.

Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to POS vending machinevery high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

An Efficient, Viable Technolo cellular gateway  gy

Previous experiments had demonstrated multi-bunch acceleration, but the team at SLAC was the first to reach the high energies of the blowout regime, where maximum energy gains at maximum efficiencies can be found. Of equal importance, the accelerated e Android vending computer lectrons wound up with a relatively small energy spread.

“These results have an additional significance beyond a successful experiment,” said Mark Hogan, SLAC accelerator physicist and one of the principal investigators of the experiment. “Reaching the blowout regime with a two-bunch configuration has enabled us to increase the acceleration efficiency to a maximum of 50 percent – high enough to really show that plasma wakefield acceleration is a viable technology for future accelerators.”

The plasma source used in the experiment was developed by a team of scientists led by Chandrashekhar Joshi, director of the Neptune Facility for Advanced Accelerator Research at UCLA. He is the UCLA principal investigator for this research, a faculty member with the UCLA Henry Samueli School of Engineering and Applied Science, and a long-time collaborator with the SLAC group.

“It is gratifying to see that the UCLA-SLAC collaboration on plasma wakefield acceleration continues to solve seemingly intractable problems one by one through systematic experimental work,” Joshi said. “It is this kind of transformative research that attracts the best and the brightest students to this field, and it is imperative that they have facilities such as FACET to carry it out.”

This animation explains how electrons can be efficiently accelerated to high energy using wakes created in a plasma.

The Next Steps

There are more milestones ahead. Before plasma wakefield acceleration can be put to use, Hogan said, the trailing bunches must be shaped and spaced just right so all the electrons in a bunch receive exactly the same boost in energy, while maintaining the high overall quality of the electron beam.

“We have our work cut out for us,” Hogan said. “But you don’t get many chances to conduct research that you know in advance has the potential to be immensely rewarding, both scientifically and practically.”

Computer simulations used in the experiments were developed by Warren Mori’s group at UCLA. Additional contributors included researchers from SLAC, the University of Oslo in Norway, Tsinghua University in China and Max Planck Institute for Physics in Germany. The research was funded by the DOE Office of Science.

Publication: M. Litos, et al., “High-efficiency acceleration of an electron beam in a plasma wakefield accelerator,” Nature, 515, 92–95 (06 November 2014); doi:10.1038/nature13882

Image: SLAC National Accelerator Laboratory

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Electron microscope image of a prototype chip using a ring of coupled oscillators to generate terahertz radiation. Silicon cannot oscillate in the terahertz range, but the design focuses most of the energy in a high harmonic. The signal radiates on the axis of the ring and can be aimed. Provided/Ehsan Afshari

A recently published paper describes how scientists at Cornell University developed a new method of generating terahertz signals using the familiar and inexpensive CMOS chip technology, generating power levels high enough for some medical applications.

Cornell researchers have developed a new method of generating terahertz signals on an inexpensive silicon chip, offering possible applications in medical imaging, security scanning and wireless data transfer.

Terahertz radiation, the portion of the electromagnetic spectrum between microwaves and infrared light, penetrates cloth and leather and just a few millimeters into the skin, but without the potentially damaging effects of X-rays. Terahertz scanning can identify skin cancers too small to see with the naked eye. Many of the complex organic chemicals used in explosives absorb terahertz radiation at particular frequencies, creating a “signature” that detectors can read. And because higher frequencies can carry more bandwidth, terahertz signals could make a sort of super-Bluetooth that could transfer an entire high-definition movie wirelessly in a few seconds.

Current methods of generating terahertz radiation involve lasers, vacuum tubes and special circuits cooled near absolute zero, often in room-sized apparatus costing thousands of dollars. Ehsan Afshari, assistant professor of electrical and computer engineering, has developed a new method using the familiar and inexpensive CMOS chip technology, generating power levels high enough for some medical applications. With further research, higher power will be possible, Afshari said, enabling such devices as handheld scanners for law enforcement.

Afshari and graduate students Yahya Tousi and Vahnood Pourahma describe the new approach in the June 8 issue of the journal Physical Review Letters.

Schematic of a ring of oscillators (gray circles) coupled to generate terahertz frequencies. Coupling circuits (blue triangles) shift the phase of the oscillations to recellular router wifiinforce the fourth harmonic. Provided/Ehsan Afshari

The ability of solid-state devices to generate high frequencies is limited by the characteristics of the material — basically, how fast electrons can move back and forth in a transistor. So circuit designers make use of harmonics — signals that naturally appear at multiples of the fundamental frequency of an oscillator. That fundamental frequency is usually set by a circuit that uses a variable capacitor called a varactor, but at terahertz frequencies varactors don’t tune sharply. Afshari has come up with a new way of tuning by coupling several oscillators in a ring, producing what engineers call a high-quality signal, where all the power goes into a very narrow frequency band.

Connect two springs and set one vibrating, and the other will begin to vibrate as well, and eventually they will settle to an equilibrium. A ring of electronic oscillators does the same, and the circuits coupling the oscillators can set the frequency at which they will lock in. In Afshari’s device the couplers also shift the phase of the signals, that is, how the peaks and valleys of the waves line up. With the right adjustment, the peaks  Industrial VPN router  and valleys cancel each other out at several harmonics but reinforce each other at one — in this case the fourth — channeling most of the power there.

In early experiments, the researchers fabricated chips that generated signals with about 10,000 times the power level previously obtained at terahertz frequencies on a silicon chip. The signal emerges along the axis of the ring, and what the researchers called an intriguing possibility is that by adjusting the couplers separately they could aim the output, making it possible to scan large areas with a narrow, high-powered beam.

The power could be increased by adding more oscillators to the ring or using multiple rings, and Afsha digital signage  ri is working with Cornell experts on gallium nitride, a chip material that can handle both higher frequencies and higher power. But Afshari said he wants to focus on less-expensive silicon. “The goal is to make a complete device on one CMOS chip,” he said. “I can envision a tiny thing you could put in a cell phone.”

The research is funded by the National Science Foundation, the U.S. Office of Naval Research and the Semiconductor Research Corp., a consortium supported by private industry and the Defense Advanced Projects Research Administration.

Images: Provided/Ehsan Afshari; Cornell Chronicle