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  • richardmitnick 5:35 pm on January 22, 2021 Permalink | Reply
    Tags: "Sensors- the other quantum revolution", As their name suggests quantum sensors use the properties of quantum physics, Centre National de la Recherche Scientifique [CNRS ] (FR), Identifying every pipe and cavity beneath our cities; anticipating a volcanic eruption; or observing brain activity in the most minute detail; these are only some of the tantalising promises made by a, Medicine; civil engineering; telecommunications; natural resources management... Quantum sensors offering both unique sensitivity and accuracy are about to revolutionise detection in a number of field, Of all the quantum technologies under development they are among the most advanced with some even emerging from the laboratory and reaching the market!   

    From Centre National de la Recherche Scientifique [CNRS ](FR): “Sensors- the other quantum revolution” 

    CNRS bloc

    From Centre National de la Recherche Scientifique [CNRS ](FR)

    01.12.2021

    1
    GyrAChip atom-chip gyrometer developed to create a GPS-free inertial navigation system measuring only a few cubic centimetres. Credit: Cyril FRESILLON / SYRTE / FIRST-TF / CNRS Photothèque.

    Medicine, civil engineering, telecommunications, natural resources management… Quantum sensors offering both unique sensitivity and accuracy are about to revolutionise detection in a number of fields.

    Identifying every pipe and cavity beneath our cities, anticipating a volcanic eruption, or observing brain activity in the most minute detail, these are only some of the tantalising promises made by a new type of instrument with unprecedented sensitivity: quantum sensors. Of all the quantum technologies under development, they are among the most advanced, with some even emerging from the laboratory and reaching the market!

    Exceptional sensitivity

    As their name suggests, quantum sensors use the properties of quantum physics, the theory that describes phenomena on the atomic scale. Central to these devices are microscopic objects (photons, atoms, electrons, etc.) that physicists can now manipulate at will, and even place within a particular quantum state, which is itself extremely sensitive to the least disturbance in the environment. Quantum sensors are built on the very same principle, which explains their remarkable receptivity to tiny signals of various kinds, such as the gravitational attraction of an object beneath our feet, or the magnetic fields emitted by our brain.

    Atom interferometers are the first quantum sensors to have harnessed this potential. These devices, which were initially developed for basic research and metrology, use a laser to cool an atom cloud consisting of a few million particles to very low temperatures, approximately one millionth of a degree above absolute zero. “In these conditions, atoms move so slowly that we can precisely estimate the forces they are subject to, such as acceleration or rotation,” explains Arnaud Landragin, who directs the SYRTE laboratory.[1]

    3
    Arnaud Landragin (in the background), laureate of the CNRS 2020 Innovation Medal and Leonid Sidorenkov, from the SYRTE laboratory, near a cold-atom source. Credit: Frédérique PLAS / SYRTE / CNRS Photothèque.

    These instruments for example can measure the acceleration of gravity, in which case they are referred to as atomic gravimeters. This is done by allowing atoms to free-fall under the effect of terrestrial attraction. During this process, the particles are subject to a series of laser pulses that place each of them within a quantum superposition – between a state in which it has not absorbed a laser photon, and another in which it has gained speed by absorbing such a photon – before making these two situations interfere. Observations are then made of the interference signal that reflects differences in path between the two states as a result of the acceleration of gravity (g), which makes it possible to work out the latter’s value. “The measurement is extremely accurate, as we can detect fluctuations in g on the order of one per billion, or the variation in gravity when rising three millimetres above the Earth’s surface!” observes Philippe Bouyer, director of the Photonics, Numerical and Nanosciences Laboratory (LP2N).[2]

    Ultra-stable atomic gravimeters

    Such precision opens the way for numerous applications, as accurate measurement of gravity provides invaluable information regarding the composition of the soil. For example, a mass of granite, an oil slick, or an underground water reservoir have distinct densities, and thus contribute to slightly different values for g on the surface. This can facilitate the exploration and management of natural resources. Similarly, by placing such a gravimeter on the slope of a volcano, geophysicists can have a better grasp of its activity, for g will be affected when pockets of magma appear or disappear near the surface. The same is true for monitoring the movement of tectonic plates in zones of seismic activity.

    4
    Muquans gravimeter on top of Mount Etna. Credit: MUQUANS.

    Researchers quickly understood the full potential of this system, and are working tirelessly to extend it beyond the laboratory. This is precisely what Landragin and Bouyer are doing: after developing an optical technique that simplified the functioning of their gravimeter, they decided in 2011 to create the Muquans company, the only one in the world to commercialise such sensors. The French firm has sold a dozen units to date, primarily to geophysical research institutes. One of its measuring instruments was even installed on top of Mount Etna this summer as part of the Newton-g European project, in order to monitor magma movement with the ultimate goal of connecting it to the volcano’s activity, and one day anticipating its eruptions.

    Increasingly compact devices

    The Muquans instrument, which consists of a cylinder measuring 70 cm in height, and a second and somewhat larger module for electronics and lasers, is relatively compact. In terms of size, it is bettered by only one other type of gravimeter, which is made up of a mass hanging at the end of a spring. Easily transportable, the latter is now the most widely used in the field. “The problem is that its measurements drift over time, so that it has to be calibrated regularly. The atomic device, on the other hand, provides an absolute measurement that remains stable, since it is based on the laws of quantum physics,” explains Landragin.

    As regards precision, another type of gravimeter, also absolute – consisting of an optical interferometer one of whose mirrors enters free fall – offers the same performance as its atomic equivalent. “The downside is that its mechanical parts are subject to considerable wear and tear, unlike the atom gravimeter, which requires little maintenance. The latter can therefore be used to make continuous readings over long durations.” This is a major asset for monitoring natural phenomena in the long term.

    These advantages explain why geophysicists are increasingly adopting this new system, especially as its size will shrink in the future. “In the next four years, our instrument’s weight will be halved to 50 kilos instead of today’s 100. This will further expand its applications,” enthuses Bruno Desruelle, president of Muquans. v

    Gradiometers for detecting buried cavities

    And there is more. Laboratories and companies such as Muquans are working on an improved version of the gravimeter, known as a gradiometer, which is not affected by tremors in the ground that can disrupt measurement. This can be achieved by using two atom clouds exposed to the same vibrations, but falling from two different heights. Comparing the signals from the two clouds makes it possible to eliminate noise interference, all while obtaining a measurement of the gravity gradient. “The gradiometer can detect small masses located at shallow depth, whereas the gravimeter is sensitive to large masses at great depth,” Desruelle points out.

    5
    Gravimeter prototype measuring the variation in the acceleration of gravity on rubidium atoms as a function of altitude. Credit: Cyril FRESILLON / SYRTE / FIRST-TF / CNRS Photothèque.

    This sensor could make life easier for civil engineering and construction companies, which must conduct lengthy and costly field studies to identify a former mine or other dangerous underground structure, and often have to dig to locate pipe networks or cables beneath street level. A gradiometer would help them save an enormous amount of time – and money.

    Accelerometers that do not drift

    With more than one string to their bow, atomic interferometers could also be used to develop a navigation system that would continue to function even in the absence of a GPS signal, a priority for the armed forces in particular. Such an autonomous mechanism already exists – involving accelerometers and gyroscopes to measure, respectively, the acceleration and rotation of a vehicle – in order to continually determine its direction and speed of movement, and thereby work out its position. But like spring gravimeters, these instruments drift over time. For example in an airliner, the instability of these inertial sensors translates into an error of approximately one hundred metres after one hour of flight. “Because they are intrinsically stable, atomic accelerometers and gyroscopes allow for much more accurate guidance,” Bouyer stresses.

    6
    Installing laser beams on the GyrAChip cold-atom gyrometer. Credit: Cyril FRESILLON / SYRTE / FIRST-TF / CNRS Photothèque.

    These atomic inertial measurement units are in use today, but only in laboratories. They are still too big to be placed on-board vehicles, and are not yet resistant enough against vibrations, which are frequent on boats and airplanes.

    Several avenues are being explored to improve them. At Thales, the French tech giant that is developing multiple quantum technologies for various fields of application, efforts are underway to miniaturise the device by relying on the innovative technique of atom chips. This once again involves laser-cooled atoms, which instead of being subject to free fall, are magnetically trapped on a chip, where they are manipulated using radio waves produced by electrical microwires. “We hope this will enable us to create an inertial sensor with a volume of just one litre by 2030,” enthuses Daniel Dolfi, in charge of the physics group at Thales Research and Technology.

    7
    Atomic chip aimed at trapping cold atoms after they are captured and cooled, using magneto-optical traps (Thales TRT, member of the FIRST-TF excellence network supported by the CNRS). Credit: Hubert RAGUET / THALES TRT / FIRST-TF / CNRS Photothèque.

    Synthetic diamonds to measure magnetic fields

    Another extremely promising quantum sensor is known as an NV (nitrogen vacancy) centre, a microscopic defect lodged in synthetic diamonds that can detect very weak magnetic fields. These impurities, which consist of a nitrogen atom and a vacancy instead of two carbon atoms, behave like single atoms: when excited by a green laser they emit red light whose intensity depends on the spin state – a quantum magnetic moment that can be represented as a small magnetic needle, and is therefore sensitive to a magnetic field – of the electrons trapped in their vicinity. By sending microwaves at the right frequency, one can create quantum superposition states, and thereby record a change in the quantity of light emitted. However, the presence of an external magnetic field will shift the position of spin states, and thus modify what is known as its resonance frequency, by a value that is proportional to the field’s intensity. By measuring the amount of red light received, the value of the magnetic field can be worked out precisely.

    “The first advantage of NV centres is that they are simple to put in place, as they function at room temperature, and do not require heavy cryogenic equipment, as is the case for other systems. This opens the way for numerous applications,” stresses Thierry Debuisschert, in charge of NV centres at Thales. For instance, some existing magnetic field sensors, called Squids, offer greater sensitivity than NV centres, but they must operate at a very low temperature.

    8
    Artist’s impression of the spectrum analyser using diamonds’ NV centres. Credit: Ludovic MAYER.

    Diamond magnetic microscopes

    The other advantage of these artificial atoms is their size. Today, it is possible to produce tiny diamonds of a few dozen nanometres that contain a single NV centre. Putting this mineral at the end of a silicon tip and bringing it very close to a material means obtaining another type of microscope, one that can identify the magnetic properties of an object in great detail when swept across its surface. “This microscope can make very fine measurements of a material’s magnetic field, with a resolution of a few dozen nanometres. It’s quite unique,” says Vincent Jacques from the Charles Coulomb laboratory (L2C),[3] who with his team, in 2012, produced the first magnetic images using NV centre microscopy.

    Since this demonstration, several start-ups have set out to develop these new-generation microscopes, with the first commercial prototypes already available on the market. This is so far the most advanced application for NV centres.

    These instruments should enable huge progress in the field of spintronics, a branch of electronics that uses the spin of electrons and not just their electrical charge. A number of materials are being considered to improve components for this electronics of the future. Identifying the best candidates requires perfect knowledge of their magnetic properties. “The NV centre microscope is the ideal tool in this effort, for it alone can probe, at room temperature, nanometric-scale magnetic fields at specific magnetic moments,” Jacques points out.

    A new imaging procedure at the cellular level

    Applications are equally promising in biology and chemistry. Since NV centres are controllable at room temperature and the diamond is not toxic, it is possible to directly place, without causing any damage, cells or molecules on the surface of a stone measuring a few millimetres, in which multiple NV centres have been embedded to boost its sensitivity to magnetic fields. The idea is to calculate the nuclear magnetic resonance (NMR) of these samples, which is to say the oscillating fields produced by the spin of atomic nuclei. “The advantage compared to other NMR techniques is sensitivity to a few spins, and even to one only,” points out Thierry Debuisschert, who coordinates the Asteriqs European project, whose goal is to explore every avenue for the use and improvement of NV centres. “This makes it possible to characterise single cells or molecules.”

    Research has already begun to this end, and there are hopes that these sensors can one day serve to analyse brain activity in detail, or to closely study the structure of a protein in space (which determines how it functions) – a substantial advantage for designing new drugs.

    Improving telecommunications

    A highly novel application for these quantum sensors is being developed at Thales. “Rather than rely on NV centres to detect a magnetic field, we could do the opposite: apply a magnetic field to a diamond in order to identify the microwave frequencies present in the environment,” Debuisschert adds. The device subsequently becomes a spectrum analyser, which can simultaneously recognise hundreds of different frequencies in the field of radar waves. This instrument could eventually enable the military to intercept communications or identify a threat (the signature of a radar or a missile). In everyday life, it would improve mobile telecommunications, since continual analysis of the frequency bands being used makes it possible to reassign them in real time to a particular operator, as necessary.

    The laboratory prototype developed by the French company has already shown the worth of this technique. The team is now working on reducing its size and increasing its sensitivity, especially by making optimal use of the red light emitted by the diamond, and by improving the crystal’s quality. The goal is to offer a sensor worthy of the name within the next five years.

    These defects in diamonds will continue to generate interest, all the more so as scientists are beginning to explore their capacity – once again using their spin state – to measure tiny electric fields and variations in temperature and pressure. In short, they’re aiming at the ultimate quantum sensor. With its many facets, no doubt this instrument has a bright future. _______________________________________________________________________________________________________
    Footnotes

    1.
    Systèmes de Référence Temps-Espace (CNRS / Observatoire de Paris / Sorbonne Université / LNE).
    2.
    CNRS / Institut d’Optique / Université de Bordeaux.
    3.
    CNRS / Université de Montpellier.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    CNRS (FR) campus via Glassdoor

    CNRS (FR) encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 2:35 pm on January 22, 2021 Permalink | Reply
    Tags: "Saturn’s tilt caused by its moons", Centre National de la Recherche Scientifique [CNRS ] (FR),   

    From Centre National de la Recherche Scientifique [CNRS ](FR): “Saturn’s tilt caused by its moons” 

    CNRS bloc

    From Centre National de la Recherche Scientifique [CNRS ](FR)

    January 18, 2021

    Melaine Saillenfest
    CNRS researcher
    melaine.saillenfest@obspm.fr

    Gwenaël Boué
    Sorbonne Université teacher-researcher
    gwenael.boue@obspm.fr

    François Maginiot
    CNRS Press Officer
    +33 1 44 96 43 09
    francois.maginiot@cnrs.fr

    1
    © Coline SAILLENFEST / IMCCE

    Two scientists from CNRS and Sorbonne University working at the Institute of Celestial Mechanics and Ephemeris Calculation (Paris Observatory – PSL/CNRS) have just shown that the influence of Saturn’s satellites can explain the tilt of the rotation axis of the gas giant. Their work, published on 18 January 2021 in the journal Nature Astronomy, also predicts that the tilt will increase even further over the next few billion years.

    Rather like David versus Goliath, it appears that Saturn’s tilt may in fact be caused by its moons. This is the conclusion of recent work carried out by scientists from the CNRS, Sorbonne University and the University of Pisa, which shows that the current tilt of Saturn’s rotation axis is caused by the migration of its satellites, and especially by that of its largest moon, Titan.

    Saturn’s moon Titan imaged by Cassini. Credit: NASA/JPL-Caltech,University of Arizona,University of Idaho.

    Recent observations have shown that Titan and the other moons are gradually moving away from Saturn much faster than astronomers had previously estimated. By incorporating this increased migration rate into their calculations, the researchers concluded that this process of gravitational pull of the satellites affects the inclination of Saturn’s rotation axis: as its satellites move further away, the planet tilts more and more.

    The decisive event that tilted Saturn is thought to have occurred relatively recently. For over three billion years after its formation, Saturn’s rotation axis remained only slightly tilted. It was only roughly a billion years ago that the gradual motion of the gravitational pull of its satellites triggered a resonance phenomenon that continues today: Saturn’s axis interacted with the path of the planet Neptune and gradually tilted until it reached the inclination of 27° observed today.

    These findings call into question previous scenarios. Astronomers were already in agreement about the existence of this resonance. However, they believed that it had occurred very early on, over four billion years ago, due to a change in Neptune’s orbit. Since that time, Saturn’s axis was thought to have been stable. In fact, Saturn’s axis is still tilting, and what we see today is merely a transitional stage in this shift. Over the next few billion years, the inclination of Saturn’s axis could more than double.

    The research team had already reached similar conclusions about the planet Jupiter [The future large obliquity of Jupiter-Astronomy and Astrophysics], which is expected to undergo comparable tilting due to the migration of its four main moons and to resonance with the orbit of Uranus: over the next five billion years, the inclination of Jupiter’s axis could increase from 3° to more than 30°.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    CNRS (FR) campus via Glassdoor

    CNRS (FR) encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 1:26 pm on December 2, 2020 Permalink | Reply
    Tags: "Researchers improve the measurement of a fundamental physical constant", , Centre National de la Recherche Scientifique [CNRS ] (FR), Characterization of the strength of interaction between light and charged elementary particles such as electrons., , , , The use of more accurate constants can help to answer fundamental questions such as the origin of dark matter in the universe.   

    From Centre National de la Recherche Scientifique [CNRS ](FR) via phys.org: “Researchers improve the measurement of a fundamental physical constant” 

    CNRS bloc

    From Centre National de la Recherche Scientifique [CNRS ](FR)

    1
    Illustration of the experimental measurement of the fine-structure constant. The background patterns in the image represent the actual Feynman diagrams used to help calculate the theoretical value of the electron magnetic moment anomaly (calculated using the fine-structure constant, among others). The scheme of the atom interferometer used for measuring the recoil velocity is represented in colour. Credit: Pierre Cladé, Saïda Guellati-Khélifa et Tatsumi Aoyama.

    The validation and application of theories in physics require the measurement of universal values known as fundamental constants.

    A team of French researchers has just conducted the most accurate measurement to date of the fine-structure constant, which characterizes the strength of interaction between light and charged elementary particles, such as electrons.

    This value has just been determined with an accuracy of 11 significant digits; improving the precision of the previous measurement by a factor of 3.

    The scientists achieved such precision by enhancing their experimental set-up, in an effort to reduce inaccuracies and to control effects that can create perturbations of the measurement.

    The experiment involves cold rubidium atoms with a temperature approaching absolute zero.

    When they absorb photons, these atoms recoil at a velocity that depends on their mass. The highly precise measurement of this phenomenon helps to improve the knowledge of the fine-structure constant.

    These results, which will appear in Nature on 3 December, open new prospects for testing the Standard Model’s theoretical predictions.

    The use of more accurate constants can help to answer fundamental questions, such as the origin of dark matter in the universe.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    CNRS (FR) campus via Glassdoor

    CNRS (FR) encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 3:45 pm on November 19, 2020 Permalink | Reply
    Tags: "Machine learning yields a breakthrough in the study of stellar nurseries", , Artificial intelligence can make it possible to see astrophysical phenomena that were previously beyond reach., , , , Centre National de la Recherche Scientifique [CNRS ] (FR), ,   

    From Centre National de la Recherche Scientifique [CNRS ] (FR) via phys.org: “Machine learning yields a breakthrough in the study of stellar nurseries” 

    CNRS bloc

    From Centre National de la Recherche Scientifique [CNRS ](FR)

    1
    Emission of carbon monoxide in the Orion B molecular cloud. Credit: J. Pety/ORION-B Collaboration/IRAM(FR).

    Artificial intelligence can make it possible to see astrophysical phenomena that were previously beyond reach. This has now been demonstrated by scientists from the CNRS, IRAM (FR), Observatoire de Paris-PSL (FR), Ecole Centrale Marseille (FR) and Ecole Centrale Lille (FR), working together in the ORION-B program. In a series of three papers published in Astronomy & Astrophysics on 19 November 2020, they present the most comprehensive observations yet carried out of one of the star-forming regions closest to the Earth.

    Quantitative inference of the H2 column densities from 3mm molecular emission: Case study towards Orion B

    Tracers of the ionization fraction in dense and translucent gas. I. Automated exploitation of massive astrochemical model grids

    C18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud: An analysis of the precision achievable when modeling spectral line within the Local Thermodynamic Equilibrium approximation

    The gas clouds in which stars are born and evolve are vast regions that are extremely rich in matter, and hence in physical processes. All these processes are intertwined at different size and time scales, making it almost impossible to fully understand such stellar nurseries. However, the scientists in the ORION-B program have now shown that statistics and artificial intelligence can help to break down the barriers still standing in the way of astrophysicists.

    With the aim of providing the most detailed analysis yet of the Orion molecular cloud, one of the star-forming regions nearest the Earth, the ORION-B team included in its ranks scientists specializing in massive data processing. This enabled them to develop novel methods based on statistical learning and machine learning to study observations of the cloud made at 240 000 frequencies of light.

    Based on artificial intelligence algorithms, these tools make it possible to retrieve new information from a large mass of data such as that used in the ORION-B project. This enabled the scientists to uncover a certain number of characteristics governing the Orion molecular cloud.

    For instance, they were able to discover the relationships between the light emitted by certain molecules and information that was previously inaccessible, namely, the quantity of hydrogen and of free electrons in the cloud, which they were able to estimate from their calculations without observing them directly. By analyzing all the data available to them, the research team was also able to determine ways of further improving their observations by eliminating a certain amount of unwanted information.

    The ORION-B teams now wish to put this theoretical work to the test, by applying the estimates and recommendations obtained and verifying them under real conditions. Another major theoretical challenge will be to extract information about the speed of molecules, and hence visualize the motion of matter in order to see how it moves within the cloud.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    CNRS (FR) campus via Glassdoor

    CNRS (FR) encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 3:25 pm on November 19, 2020 Permalink | Reply
    Tags: "Uncovering the hidden side of storms: France's Taranis satellite to launch in November", Centre National de la Recherche Scientifique [CNRS ] (FR), , Sprites; elves; jets… few people know that scientists habitually use such other-worldly words to describe transient luminous events or TLEs.   

    From Centre National de la Recherche Scientifique [CNRS ] (FR) via phys.org: “Uncovering the hidden side of storms- France’s Taranis satellite to launch in November” 

    CNRS bloc

    From Centre National de la Recherche Scientifique [CNRS ] (FR)

    via


    phys.org

    Illustration of the TARANIS. Credit: CNES/ill./SATTLER Oliver, 2012.

    TARANIS – Laboratoire de Physique et Chimie (FR) schematic

    3
    Credit: CNRS

    Sprites, elves, jets… few people know that scientists habitually use such other-worldly words to describe transient luminous events or TLEs, light flashes that occur during active storms just a few tens of kilometers over our heads. Few people also know that storms can act as particle accelerators generating very brief bursts of X-rays and gamma rays. But what are the physical processes and mechanisms behind these phenomena discovered barely 30 years ago? Do they impact the physics and chemistry of the upper atmosphere, the environment or even humans? Such are the questions facing the French Taranis satellite that will be riding aloft during the night of 16 to 17 November atop a Vega launcher from the Guiana Space Center, an all-French mission involving research scientists from CNES, the national scientific research center CNRS, the atomic energy and alternative energies commission CEA and several French universities.

    TLEs and terrestrial gamma-ray flashes (TGFs) are seen all over the world where storms occur. But because we don’t know enough about them, they don’t feature in the toolbox of climatologists and meteorologists. Are they implicated in the increasing number of extreme weather events? If so, they could be modeled and factored into forecasts in real time. Although Taranis is first and foremost a fundamental research satellite, the data it is set to deliver on Earth’s thermal and climate mechanisms could serve more operational applications like climatology and weather forecasting.

    Elves, sprites, sprite halos, blue jets and even pixies or gnomes are just some of the whimsical names given to the range of phenomena in the generic family of TLEs—a poetic lexicon that contrasts sharply with their violence. These ephemeral upper-atmosphere events occur between the tops of storm clouds and an altitude of 90 kilometers. First predicted as early as 1920, their existence was not confirmed until the nineties. They have since been recorded by numerous ground and space observations. Elves take the form of an expanding glow of light, appearing at an altitude of 90 kilometers and lasting no more than one millisecond; an active storm may produce thousands of them in the space of a few hours. Occurring between 40 and 90 kilometers above Earth’s surface, sprites have a complex structure of branches and tendrils and can last for up to 10 milliseconds. Blue jets appear at the top of storm clouds and propagate to altitudes of up to 50 kilometers. Occasionally, ‘gigantic’ jets may propagate up to 90 kilometers.

    TGFs were first observed scientifically in 1994 by the Compton Gamma-Ray Observatory (CGRO), a NASA spacecraft deployed from the U.S. space shuttle Atlantis.

    NASA Compton Gamma Ray Observatory

    In certain conditions, storms generate a very short burst of gamma photons. TGFs were for a time considered a rare occurrence accompanying sprites; we now know they are generated by electric activity in clouds. For lack of the right instruments, the Italian AGILE satellite (2007) and U.S. Fermi space telescope (2008) were unable to fully confirm current hypotheses on the mechanisms that generate them or estimate their number. Taranis will therefore bring new insights into how they are generated and their radiation impact, which has never been measured before.

    In France, the atomic energy agency CEA first turned its attention to these transient events and their impact in 1993. On 9 December 2010, the project got the official go-ahead from CNES’s Board of Directors. Taranis is an all-French mission with science goals set by French research laboratories. In addition to CEA, CNRS is closely involved through several of its affiliated research laboratories1: the LPC2E environmental and space physics and chemistry laboratory is coordinating development of the science payload, is responsible for the science mission center and is contributing instruments; the IRAP astrophysics and planetology research institute, the LATMOS atmospheres, environments and space observations laboratory and the APC astroparticles and cosmology laboratory are contributing to the payload.

    Other instruments on Taranis include outside contributions from Stanford University and Goddard Space Flight Center (GSFC) in the United States, the Institute of Atmospheric Physics (IAP) and Charles University in the Czech Republic and the Space Research Center of the Polish Academy of Sciences (CBK).

    Taranis looks somewhat different, as in place of the aluminized or gold-plated Mylar insulation traditionally used on satellites it is coated with a special black and white paint. This is not just attention to esthetic detail, the purpose of the paint being to avoid interfering with the surrounding electric field and prevent reflected light disrupting the optical sensors. A less visible but key feature is the original design of its payload, comprising eight instruments operated as a single unit thanks to MEXIC, the brain of Taranis that powers and synchronizes the instruments and manages the payload, executes the trigger strategy to capture an event and even handles the transfer of selected data to mass memory.

    Taranis’ payload close up:

    XGRE: three X-ray and gamma-ray detectors for measuring high-energy photons (50 keV to 10 MeV) and relativistic electrons (1 MeV to 10 MeV) – APC/IRAP/CNES
    MCP (MC-U and PH-U): two cameras (10 images per second) and four photometers to measure luminance in different spectral bands—CEA/CNES
    IDEE: two high-energy electron detectors (70 keV to 4 MeV) – IRAP/Charles University
    IMM: three-axis magnetometer to measure the alternating magnetic field (5 Hz to 1 MHz) – LPC2E/Stanford University
    IME-HF: HF antenna for measuring the high-frequency electric field (100 kHz to 35 MHz) – LPC2E/IAP
    IME-BF: instrument for measuring the low-frequency electric field (DC to 1 MHz) – LATMOS
    SI: ion probe to determine thermal plasma fluctuations—GSFC/LATMOS
    MEXIC: two electronic units comprising eight analysers, each connected to an instrument. It powers each instrument, handles payload modes and interfaces with mass memory and the onboard computer. MEXIC will also be tasked with synchronizing the instruments when events are detected (TLEs by MCP’s photometers, TGFs by XGRE, electron beams by IDEE, wave bursts by IME-HF) – LPC2E/CBK

    For two to four years, Taranis will scan regions of the sky where storm activity is intense and the probability of seeing TLEs and/or TGFs high. While it may be a national program, its results are eagerly awaited by the wider international scientific community. In atmospheric chemistry and physics, environmental science, climatology, high-energy astrophysics and many more fields besides, Taranis is set to reveal new insights—and science efforts won’t end there, as the mission will undoubtedly pave the way for future investigations.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    CNRS (FR) campus via Glassdoor

    CNRS (FR) encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
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