Friday, April 30, 2021

The effect of a strongly stratified layer in the upper part of Mercury's core on its magnetic field

Kolhey, Patrick; Heyner, Daniel; Wicht, Johannes; Glassmeier, Karl-Heinz
May 2020


In the 1970's the flybys of NASA's Mariner 10 spacecraft confirmed the existence of an internally generated magnetic field at Mercury. 
The measurements taken during its flybys already revealed, that Mercury's magnetic field is unique along other planetary magnetic fields, since the magnetic dipole moment of ~190 nT ∙ RM3 is very weak, e.g. compared to Earth's magnetic dipole moment. 

The following MESSENGER mission from NASA investigated Mercury and its magnetic field more precisely and exposed additional interesting properties about the planet's magnetic field. The tilt of its dipole component is less than 1°, which indicates a strong alignment of the field along the planet's rotation axis.

 Additionally the measurement showed that the magnetic field equator is shifted roughly 0.2 ∙ RM towards north compared to Mercury's actual geographic equator.

Since its discovery Mercury's magnetic field has puzzled the community and modelling the dynamo process inside the planet's interior is still a challenging task.

Adapting the typical control parameters and the geometry in the models of the geodynamo for Mercury does not lead to the observed field morphology and strength. Therefore new non-Earth-like models were developed over the past decades trying to match Mercury's peculiar magnetic field. One promising model suggests a stably stratified layer on the upper part of Mercury's core. Such a layer divides the fluid core in a convecting part and a non-convecting part, where the magnetic field generation is mainly inhibited. As a consequence the magnetic field inside the outer core is damped very efficiently passing through the stably stratified layer by a so-called skin effect. Additionally, the non-axisymmetric parts of the magnetic field are vanishing, too, such that a dipole dominated magnetic is left at the planet's surface.

In this study we present new direct numerical simulations of the magnetohydrodynamical dynamo problem which include a stably stratified layer on top of the outer core. We explore a wide parameter range, varying mainly the Rayleigh and Ekman number in the model under the aspect of a strong stratification of the stable layer. We show which conditions are necessary to produce a Mercury-like magnetic field and give a inside about the planets interior structure.


Recommend this post and follow
 Sputnik's Orbit



Posted by Chuck in Space
Posted by on No comments:

Hidden Winds on Jupiter May Be Messing with Its Enormous Magnetic Field

By Rafi Letzter May 21, 2019

This image illustrates Jupiter's magnetic fields at a single moment in time.
 (Image credit: NASA/JPL-Caltech/Harvard/Moore et al.)

Jupiter's magnetic field has changed since the 1970s, and physicists have proved it.

That's not exactly a surprise. Earth's magnetic field, the only planetary field for which we have good ongoing measurements, changes all the time. But the new information is important, because these small changes reveal hidden details of a planet's internal "dynamo," the system that produces its magnetic field.

In a paper published May 20 in the journal Nature Astronomy, a team of researchers looked at magnetic field data from four past missions to Jupiter (Pioneer 10, which reached Jupiter in 1973; Pioneer 11, which reached Jupiter in 1974; Voyager 1, which reached Jupiter in 1979; and Ulysses, which reached Jupiter in 1992). [10 Places in the Solar System We'd Most Like to Visit]

They compared that data to a map of the planet's magnetic field produced by the spacecraft Juno, which conducted the most recent and most thorough probe of the giant planet. In 2016, Juno orbited very close to Jupiter, passing from pole to pole, gathering detailed gravitational and magnetic field data. That allowed researchers to develop a thorough model of the planet's magnetic field and some detailed theories as to how it's produced.

The researchers behind this paper showed that data from those four older probes, though more limited (each of them just swung by the planet once), didn't quite fit with the 2016 model of Jupiter's magnetic field.

"Finding something as minute as these changes in something so immense as Jupiter's magnetic field was a challenge," Kimee Moore, a Juno scientist at Harvard and lead author on the paper, said in a statement. "Having a baseline of close-up observations over four decades long provided us with just enough data to confirm that Jupiter's magnetic field does indeed change over time."

One challenge: The researchers were only interested in changes to Jupiter's internal magnetic field, but the planet also has magnetism coming from its upper atmosphere. Charged particles from volcanic eruptions on Io, Jupiter's most volatile moon, end up in the Jovian magnetosphere and ionosphere (a region of charged particles in the outer reaches of Jupiter's atmosphere) and can also change the magnetic field. But the researchers developed methods to subtract those effects from their data set, leaving them with data based almost entirely on the internal dynamo of the planet.

So the question was, what caused the changes to happen? What's going on in Jupiter's dynamo?

The researchers looked at several different causes of magnetic field changes. Their data most closely matched the predictions of a model in which winds in the planet’s interior change the magnetic field.

Jupiter's southern hemisphere, as photographed by NASA's Juno spacecraft. 
(Image credit: Gerald Eichstädt/Seán Doran/NASA/JPL-Caltech/SwRI/MSSS)

"These winds extend from the planet's surface to over 1,860 miles (3,000 kilometers) deep, where the planet's interior begins changing from gas to highly conductive liquid metal," the statement said.

In truth, researchers can't see that deep into Jupiter, so the depth measurements are really best estimates, with several uncertainties, the researchers wrote in the paper. Still, scientists have robust theories to explain how the winds behave.

"They are believed to shear the magnetic fields, stretching them and carrying them around the planet," the statement said.

Most of those wind-driven changes seem to be concentrated in Jupiter's Great Blue Spot, a region of intense magnetic energy near Jupiter’s equator. (This is not the same thing as the Great Red Spot.) The northern and southern parts of the blue spot are shifting east on Jupiter, and the central third is shifting west, causing changes to the planet's magnetic field.

"It is incredible that one narrow magnetic hot spot, the Great Blue Spot, could be responsible for almost all of Jupiter's secular variation, but the numbers bear it out," Moore said in the statement. "With this new understanding of magnetic fields, during future science passes we will begin to create a planetwide map of Jupiter's [magnetic] variation. It may also have applications for scientists studying Earth's magnetic field, which still contains many mysteries to be solved." 


Recommend this post and follow Sputnik's Orbit
Posted by on No comments:

Saturn's Magnetosphere

- Marcia Burton, NASA Cassini probe. (no author credit given)

Saturn's Magnetosphere

Measurements from Cassini totally changed our understanding of Saturn’s magnetosphere, yet many questions still remain.
Overview: Scientists had little information about Saturn’s magnetosphere because magnetic fields are invisible and are best studied from within. Cassini studied Saturn's magnetosphere like never before by mapping the magnetic field, studying the flow of excited gases under its influence and observing how it affects Saturn’s auroras. The results have provided powerful insights about how Saturn's inner workings affect the planet's atmosphere and the space around it.

Forces deep inside Saturn create a giant magnetic bubble around the planet, called the magnetosphere, which exerts a powerful influence on the space environment near the planet. Saturn's magnetic field is created as material cycles deep within the planet's fluid interior.

Outside Saturn's magnetosphere, a million-mile-per-hour flow of electrically charged particles (electrons and ions) from the sun, called the solar wind, spreads out through the solar system. When the solar wind encounters Saturn's own magnetic field, the protective bubble of Saturn’s magnetosphere forms. Outside the planet's magnetosphere, the sun's magnetic forces dominate, while inside the planet's protective bubble, the magnetic forces of Saturn reign.

In a similar way, Earth's magnetic field creates a much smaller magnetosphere that protects us from harmful particles emitted by the sun and other space phenomena.

Saturn's magnetic field has north and south poles, like those on a bar magnet, and the field rotates with the planet. On Jupiter and Earth, the magnetic fields are slightly tilted with respect to the from the planets' rotation axes – this tilt is the reason we say compass needles point to "magnetic north" rather than true north. But Saturn's magnetic field is almost perfectly aligned with the planet's rotation.

The structure and strength of the magnetic field at different locations within the magnetosphere can tell us about Saturn's interior structure and reveal unseen details about how the planet interacts with the solar wind that fills interplanetary space.

Magnetic fields themselves are invisible, but we can study them with a diverse set of instruments, like those that were on Cassini. Before the Cassini spacecraft arrived at Saturn, scientists had only brief glimpses at what Saturn's magnetosphere was like. The knowledge was based on flybys by the Pioneer and Voyager spacecraft in the late 1970s and early 1980s. But these spacecraft – from entry to exit–only spent a matter of days in Saturn's magnetosphere.

An aurora on the south pole of Saturn caused in part by Saturn's magnetosphere. 
Credit: NASA, ESA, J. Clarke (Boston University), and Z. Levay



Equipped with a much more capable suite of instruments and ample time in orbit around Saturn, Cassini confirmed some of the earlier measurements but also revealing some remarkable differences. For example, Cassini’s cameras took images of auroras formed by charged particles slamming into the planet's upper atmosphere. And by measuring the flow of charged particles around the spacecraft, Cassini observed how Saturn's rings and moons release material into the magnetosphere, interacting with and modifying it.

“Fields and particles instruments on the Cassini spacecraft have revealed that Enceladus powers a huge plume of water ice particles and dust grains, the dominant source of Saturn’s E ring,” said Marcia Burton, magnetospheres and plasma science investigation scientist at NASA’s Jet Propulsion Laboratory. “Our first indication of the plume's presence was from observations of how Saturn's magnetic field was deflected.”

In addition to their magnetic effects, magnetospheres produce radio waves. Saturn's magnetic field is far weaker than Jupiter's, and unlike the more intense Jovian radio emissions, Saturn's radio signals are not powerful enough to be detected from Earth. Cassini and previous spacecraft that visited Saturn measured a type of radio emissions that scientists had expected would reveal the rotation period of Saturn's magnetic field. This rotation rate was thought to be the true length of the planet's day, since gas giants have no solid surface and their cloud bands move at various speeds.

Puzzlingly, the rotation rate Cassini measured was slower than that measured 25 years earlier by the Voyager spacecraft, and that rate varied during Cassini's 13 years orbiting Saturn. Since an actual slowing of the giant planet's rotation was highly unlikely, scientists had a mystery on their hands. Various ideas have been proposed; some scientists suggested that material blasted into space by the geologic activity on Enceladus was to blame. Apparently Saturn's magnetic field is slowed down as it drags through the ring of particles that litter the orbit of Enceladus. Other scientists have suggested that this strange signature originates in the upper atmosphere or ionosphere.

“Measurements from Cassini have totally changed our understanding of Saturn’s magnetosphere, yet many questions still remain,” said Burton.



Recommend this post and follow 
Sputnik's Orbit

Posted by on No comments:

SPACE - S0 - 20210430 - Star-Planet Energy, Master the Disaster

SPACE - S0 - 20210430 - Star-Planet Energy, Master the Disaster

Good Morning, 0bservers!

   
    
Solar winds stayed mostly steady in the 320-340 KPS range yesterday until around 1900 UTC, when they jumped up to about 360 KPS when the Bt/Bz polarities almost touched on the upper chart. That didn't seem to upset the Phi Angle at the same time, and speeds dropped even lower, in the 300-320 KPS range, but at last reading it has gone back up to 350 KPS. Particle Density continued to climb until around midnight UTC before leveling off, while Temperatures took a small upward bump around the same time as the speed bump but remained elevated. We did see a polarity shift in the Phi Angle around 0130-0200 UTC, now in the 180 range, but it doesn't seem to have had a negative effect on the other readings. The KP-Index remains green, with mostly KP-2 readings. Still waiting for those coronal hole streams to up those numbers a bit, but at most we should only see minor geomagnetic storms through the weekend. Magnetometer readings are nominal, with the peak and valley a bit more pronounced than yesterday, but still well within expected levels. Electron Flux readings again flirted with the alert threshold line, but don't appear to have crossed it (significantly), and Proton Flux readings remained nominal. We did see a pretty good upper-B Class flare spike on the X-Ray Flux around 2200 UTC, preceded by two smaller spikes, with another surge into lower-B Class around 0300 UTC. Background radiation has since dropped a bit lower into the A Class range. The video loops were all wonky (yes, that is a scientific term) for almost 12 hours yesterday, but it looks like they were able to fix the issue and the Sun has returned to center frame. The last of the Northern coronal hole system is passing the midpoint, where we can expect some solar wind impact in the next 48-72 hours (apart from the smaller stuff already on its way).

Please Recommend this page and be sure to follow the Sputnik's Orbit 


AND WHILST YOU ARE HERE BE SURE TO FOLLOW AND RECOMMEND THE COCONUT WHISPERER https://disqus.com/home/forum/the-coconut-whisperer/
Posted by on No comments:

Thursday, April 29, 2021

Using cosmic-ray neutron bursts to understand gamma-ray bursts from lightning

APRIL 28, 2021, by Los Alamos National Laboratory

A lightning mapper at the High Altitude Water Cherenkov (HAWC) Cosmic Ray Observatory in Mexico unexpectedly observed that gamma rays produce more neutrons than previously known. 
Credit: Jordan Goodman, HAWC Collaboration (NSF.gov)

Analysis of data from a lightning mapper and a small, hand-held radiation detector has unexpectedly shed light on what a gamma-ray burst from lightning might look like—by observing neutrons generated from soil by very large cosmic-ray showers. The work took place at the High Altitude Water Cherenkov (HAWC) Cosmic Ray Observatory in Mexico.

"This was an accidental discovery," said Greg Bowers, a scientist at Los Alamos National Laboratory and lead author of the study published in Geophysical Research Letters. "We set up this system to study terrestrial gamma-ray flashes—or gamma-ray bursts from lightning—that are typically so bright you can see them from space. The idea was that HAWC would be sensitive to the gamma-ray bursts, so we installed a lightning mapper to capture the anatomy of the lightning development and pinpoint the lightning processes producing them."

The team, including Xuan-Min Shao and Brenda Dingus also from Los Alamos, used a small, handheld particle detector, expecting that a terrestrial gamma-ray flash would generate a clear gamma-ray signal in the small particle detector.

"Our system ran for almost two years, and we saw a lot of lightning," said Bowers. But during those storms, they did not observe anything that looked like terrestrial gamma-ray flashes. "We did, however, see large count-rate bursts during clear, fair-weather days, which made us scratch our heads."

HAWC data gathered during these times showed that, in every case, the large array that comprises HAWC had been overwhelmed by extremely large cosmic-ray showers—so large that the Los Alamos researchers couldn't estimate their size.

UC Santa Cruz collaborator David Smith found that these fair-weather bursts had previously been observed by scientists in Russia, who called them "neutron bursts," and determined that they were the result of neutron production in the soil around the impact point of cosmic ray shower cores.

Previous work that simulated these events had only considered hadrons—a type of subatomic particle—in the core of the showers. In addition to hadrons and other particles, cosmic-ray shower cores also contain a lot of gamma rays.

For this work, William Blaine, also of Los Alamos, simulated large cosmic ray-showers, and included both hadrons and gamma rays. "We were able to match our observations with the simulations," said Bowers. "We found that the gamma rays produce the same type of neutron burst as the hadrons."

This study suggests that any natural phenomena that produces a beam of gamma-rays pointed towards the ground (such as downward terrestrial gamma-ray flashes), could produce a similar "neutron burst" signature. This is significant for future terrestrial gamma-ray flash observation modeling efforts.

"It tell us that you can't just model the gamma rays hitting your detector, you'll also have to consider the neutron burst that's happening nearby," said Bowers.

The HAWC Observatory comprises an array of water-filled tanks high on the flanks of the Sierra Negra volcano in Puebla, Mexico, where the thin atmosphere offers better conditions for observing gamma rays. When gamma rays strike molecules in the atmosphere they produce showers of energetic particles. When some of those particles strike the water inside the HAWC detector tanks, they produce flashes of light called Cherenkov radiation. By studying these Cherenkov flashes, researchers reconstruct the sources of the showers to learn about the particles that caused them.



Recommend this post and follow 
Sputnik's Orbit







Posted by Chuck in Space

Posted by on No comments:

There Could Be 14 Antimatter Objects Lurking Out There in The Milky Way

MICHELLE STARR, 29 APRIL 2021

(S. Dupourqué/IRAP)

In a map of the gamma-ray sky - the highest energy electromagnetic radiation streaming through our Universe - 14 objects could be hiding a big secret.

In a new analysis of the properties of that radiation, a team of astrophysicists have determined that it's consistent with what we'd expect from stars made of antimatter - hypothetical objects known as antistars.

This would be absolutely huge if true - it could help resolve one of the biggest mysteries in the Universe, that of all the missing antimatter. But there are still a few other things those 14 objects could be.

Every particle of matter that makes up the stuff we see around us - like electrons and quarks - has a counterpart with identical features, except for one thing: an opposite charge. It's thought that particles and antiparticles were produced in equal quantities at the beginning of the Universe.

When a particle and its antiparticle collide, they annihilate each other in a burst of gamma radiation, which suggests that they should still exist in equal quantities (or nothing exists at all, a cheery thought), but for some reason, only trace amounts of antimatter have been detected.

We've sort-of grown accustomed to the idea that pretty much none of the 'original' antimatter remains in the Universe. Physicists have developed models and explanations based on that assumption, it's a whole big thing.

Then along came the Alpha Magnetic Spectrometer experiment (AMS-02) aboard the International Space Station. A few years ago, it made tentative detections of antihelium - a discovery that, if validated, means enough fundamental antiparticles could have stuck around to clump into whole atoms of antimatter.

But where? According to a team of astronomers led by Simon Dupourqué at the Institut de Recherche en Astrophysique et Planétologie in France, maybe it's hiding in the form of antistars in the Milky Way.

Because antistars would behave pretty much like normal stars, they would be pretty hard to detect - unless normal matter, such as interstellar dust, accreted onto the star's surface, where it would be annihilated by the antimatter of the star.

In turn, this would produce a gamma ray excess at specific energies that, theoretically, we could detect.

We haven't detected the signature annihilation gamma-ray bump in the cosmic microwave background (that's the radiation left over from the Big Bang), or gamma-ray surveys of the Milky Way. For their study, Dupourqué and his team focused on 10 years of data from the Fermi Gamma-ray Space Telescope, closely examining the 5,787 gamma-ray sources therein to look for signs of what might be matter-antimatter annihilation.

They looked specifically for gamma-ray signatures consistent with proton-antiproton annihilation, as well as a point-like geometry in the source itself - that is, it looks like a star. Of the 5,787 sources, just 14 could be considered antistar candidates.

It's not hugely likely that these 14 objects are antistars; they could easily turn out to be known gamma-ray emitters such as pulsars or black holes. But they give us a starting point for estimating the number of antistars that could be hiding in the Milky Way.

By simulating antistar accretion processes, and assuming that antistars have similar properties to normal stars, the team derived an upper limit for this number. In the Milky Way disk, just 2.5 stars out of every million could be antistars.

Outside of the Milky Way disk, in the galactic halo, it could be a very different story. The space above and below the disk is much more empty of gas and dust, which means there's less material to accrete onto any potential antistars.

Without the accretion of normal matter, these antistars would not give off a gamma-ray excess, and would more easily evade detection in gamma-ray surveys; in fact, they could have been hiding since the beginning of the Universe.

According to the team's calculations, it's unlikely that there are any antistars within the immediate vicinity of the Solar System. This means that the source of the anti-helium would more likely be a population of these halo antistars.

You may also have noticed that 2.5 out of 1 million stars is not even close to equal proportions of antimatter and matter - so the discovery of antimatter stars would not resolve the problem of the missing antimatter.

In fact, it would probably raise the not-insignificant question of how clumps of antimatter had managed to survive when surrounded by material that would wipe it out in a flash of light.

The team's work is aimed at providing new, tighter constraints on the number of antistars that might be out there, so that future work has a better baseline to work from in trying to understand where and how antiparticles might be found in the Milky Way galaxy.

And continuing to monitor those 14 candidates will help determine whether they are antistars, or something more mundane, like a pulsar, or a black hole.

Which may be one of the only times the word "mundane" might apply to those strange, strange objects.

The research has been published in Physical Review D.


Recommend this post and follow 
Sputnik's Orbit
https://disqus.com/home/forum/thesputniksorbit-blogspot-com/






Posted by Chuck in Space

Posted by on No comments:

SPACE - S0 - 20210429 - USA Earthquakes, Dusty Wave, Oceanic Changes

SPACE - S0 - 20210429 - USA Earthquakes, Dusty Wave, Oceanic Changes

Good Morning, 0bservers!

   
    
A quieter day yesterday up on ol' Sol. Wind speeds continued to track down after yesterday's report, now in the 320-340 KPS range. Particle Density started a gentle rise as the speed was going down, and Temperature readings took a significant drop around 0400 UTC from 5000°K to around 4200°K. It was about the same time that the two magnetic indices (Bt and Bz) almost met on the upper portion of the DSCOVR chart. Phi Angle has been mildly variable throughout the period, but nothing worrisome. The KP-Index is remaining in the calm range. Magnetometer readings have returned to a normal sine wave pattern. Proton Flux readings remain nominal, but the Electron Flux just touched the Alert Threshold level yesterday early evening. X-Ray Flux readings were also pretty calm (relatively) with just one mid-Class B spike around 0900 UTC yesterday, and the background radiation stabilizing in upper-Class A again afterward. The solar video loops did something REALLY weird, though. Just before 2100 UTC, the image of the sun (which always remains in the center) suddenly jumped to the far right of the screen, so you can only see the left (Eastern) half of the star. However, from what I could see, the bulk of the Northern coronal hole system has passed central heliographic longitude (that's science-talk for "the middle"), and we should begin feeling the effects from that in the next day or so. The large and long sunspot group is getting closer to the Western lim, but we're still at risk, whereas its leading and smaller cousin is close to crossing out of range.

Please Recommend this page and be sure to follow the Sputnik's Orbit 


AND WHILST YOU ARE HERE BE SURE TO FOLLOW AND RECOMMEND THE COCONUT WHISPERER https://disqus.com/home/forum/the-coconut-whisperer/
Posted by on No comments:

Wednesday, April 28, 2021

SPACE - S0 - 20210428 - Electric Earth, Storm Alert, Axion Fail

SPACE - S0 - 20210428 - Electric Earth, Storm Alert, Axion Fail

Good Morning, 0bservers!

   
    
We saw the enhanced solar winds for most of yesterday, with a very brief spike to 540 KPS around 2000 UTC, but just before midnight the speeds lowered precipitously. In the span of about four hours the speed dropped by 100 KPS, with the current range in the 380-400 KPS zone. Looks like it may have been driven by a slow shift in the Phi Angle it went from 0° to 180° over a few hours. Temperatures also dropped below 5000°K around the same time, and Particle Density also continued a steady downward slope with only a few brief upward spikes. The KP-Index was a lot calmer after the two KP-3 readings early yesterday morning, now in the KP-1 to KP-2 range (with a KP-0 sneaking in last night for good measure. The Magnetometer went from a sine wave in the previous report to almost flatline yesterday, a very shallow up-and-down movement. Proton Flux and Electron Flux remain nominal. X-Ray Flux readings had a few minor spikes into mid-Class B range, but the background radiation levels are slowly moving back into upper-Class A. The main body of the Northern coronal hole system is passing the midpoint now, with a couple smaller holes forming and passing just South of the equator. 

Please Recommend this page and be sure to follow the Sputnik's Orbit 


AND WHILST YOU ARE HERE BE SURE TO FOLLOW AND RECOMMEND THE COCONUT WHISPERER https://disqus.com/home/forum/the-coconut-whisperer/
Posted by on No comments:

Tuesday, April 27, 2021

A two-qubit engine powered by entanglement and local measurements

APRIL 26, 2021: FEATURE, - by Ingrid Fadelli , Phys.org



Credit: Bresque et al.



Researchers at Institut Néel-CNRS, University of Saint Louis and University of Rochester recently realized a two-qubit engine fueled by entanglement and local measurements. This engine's unique design, outlined in a paper published in Physical Review Letters, could open up exciting possibilities for thermodynamics research and inform the development of new quantum technologies.

"Our paper is based on a very simple and deep effect of quantum mechanics: Measuring a quantum system disturbs the system, i.e., changes its state in a random way," Alexia Auffèves, one of the researchers who carried out the study, told Phys.org. "As an immediate consequence, the measuring device provides both energy and entropy to the quantum system, playing a role similar to a hot source fueling a thermal engine. The noticeable difference is that here, the fuel is not thermal, but quantum."

A few years ago, Auffèves and some of her colleagues at Institut Néel-CNRS introduced the proof of concept for a measurement-fueled engine based on a single qubit. This was the first of a series of proposals that revealed the energetic counterpart of measurement devices.

So far, measurement processes were typically modeled using classical theoretical approaches. In their new paper, the researchers took a bold step forward by opening 'the black box' of measuring devices and looking at it from a quantum physics perspective.

"We specifically considered the creation of quantum correlations between the system to measure and a 'quantum meter,'" Auffeves said. "We tracked the energy and entropy flows along this process, unveiling the microscopic origin of the measurement fuel. This was the most important objective of our work."

In their study, Auffeves and her colleagues thus focused on so-called 'composite systems." Their analysis ultimately led to the design of a measurement-powered engine based on entangled qubits. In addition to local measurements, this engine is fueled by a physical phenomenon known as quantum entanglement. Entanglement occurs when a set of particles interact or remain connected such that the actions performed by one affect the other, even if there is a significant distance between them.

The new engine proposed by the researchers has two qubits. A qubit is a quantum system with two energy states: the ground state |0> and the excited state |1>,

"When a qubit is measured in |1>, one can deterministically extract a quantum of energy from it, dubbed a photon," Auffèves said. "When the photon is released, the qubit is back to |0> by energy conservation. Respectively, when the qubit is in |0>, one can provide one photon to excite it in the |1> state."

Auffèves and her colleagues played with two qubits of different colors: a red one and a blue one. The red qubit exchanges red photons, while the blue one exchanges blue photons. Notably, the red qubit carries less energy than the blue qubit.

The protocol used by the researchers initially provides a red photon to the red qubit, preparing |1a > while the blue qubit is |0b>. Subsequently, the qubits interact by exchanging photons with each other, becoming entangled.

"We then measured the blue qubit," Auffeves said. "If it is measured in |0b> we are back to the initial state, and the process restarts. If it is measured in |1b> a blue photon can be extracted. Since blue photons are more energetic than red ones, one gains energy from the process on average. As we show and analyze, this energy comes from the measuring device."

The measurement-powered engine proposed by Auffèves and her colleagues relies on a composite working substance, and entanglement plays a crucial role in its fueling mechanism. The researchers were able to carry out a quantitative assessment of the two physical resources brought by quantum measurement, namely information and fuel. In addition, they examined the effects of these resources on the engine's performance.

"Our findings provide new insights into the fundamental energetic resources at play when a quantum system is measured, or equivalently, when quantum correlations are created between a quantum system and a quantum meter," Auffèves said. "Originally, these results are valid in the absence of a well-defined temperature as the only considered source of noise is measurement itself."

Auffèves and her colleagues were among the first to extend measurement-powered engines to composite working substances and to offer a microscopic interpretation of the fueling mechanism. Their findings could help to extend concepts related to thermodynamics to quantum sources of noise, such as those that can appear inside a cryostat.

In the future, the researchers' work could inspire other teams to realize similar engines. In addition, their study could open up an entirely new field of research, which they suggest could be called "quantum energetics."

"Our results shed new light on the measurement postulate in quantum mechanics," Auffèves said. "Since this mechanism still feeds fundamental debates, one can hope that quantum energetics provides new measurable quantities to distinguish between the various interpretations of quantum mechanics. On a more applied side, the energetic footprints of quantum measurement and entanglement will have an impact on the energy cost of quantum technologies and their potential for scalability."



Recommend this post and follow
 Sputnik's Orbit



Posted by Chuck in Time
Posted by on No comments:

SPACE - S0 - 20210427 - More CMEs Erupt, Super-Flare Confirmations, Earth Rotation Glitches

SPACE - S0 - 20210427 - More CMEs Erupt, Super-Flare Confirmations, Earth Rotation Glitches

Good Morning, 0bservers!

   
    
Solar wind speeds started out yesterday around 480 KPS, but they encountered a lot of swing from 0500-1400 UTC due to the messed up Phi Angle readings, which had them jumping up and down in the 440-480 KPS range, at which point they climbed above 520 KPS (still remaining variable). Around 0200 UTC there was another Phi Angle shift to stability, which caused a brief spike in Particle Density and a deep drop in speed, before restabilizing to the 460-500 KPS range. Particle Density, for its part, remained mostly steady and low yesterday and this morning except for that sort of double-jump (two hours apart) mentioned above. Temperatures also remained steady (above 5000°K) for the period, with one solitary upward jump due the the Phi Angle. The two previous early morning reports on the KP-Index (0300-0600 UTC) showed minor geomagnetic storms, but since that point we've been in the green, the latest reports showing KP-3 readings. The Magnetometer readings are a nominal sine wave structure today, and the Proton Flux/Electron Flux are also well within norms. There was a brief X-Ray Flux spike into the Class C flare range yesterday around 0300, with a couple more Class B spikes before and after noon UTC, but since then the readings have stabilized, with background radiation riding the line of Class A. No obvious surges or spikes on the video loop at 193Å, but there did seem to be some intra-atmospheric releases near the South Pole. The large cluster of coronal holes in the North are now passing central heliographic longitude, and that nasty-looking pair of sunspots are well past the center, but still a risky affair. The Magnetogram seems to show they're starting to merge into one, with Beta-Gamma-Delta complexity and a latitudinal layout. We're still at risk from a strike should that system (at least 20 planetary diameters in length) decide to get nasty.

It's been a long week, folks. Nearly 80 hours again for the On-Call period. Exhausting yet exhilarating. Still, I feel like I need a nap - until Thursday... ;) 

Please Recommend this page and be sure to follow the Sputnik's Orbit 


AND WHILST YOU ARE HERE BE SURE TO FOLLOW AND RECOMMEND THE COCONUT WHISPERER https://disqus.com/home/forum/the-coconut-whisperer/
Posted by on No comments:

Monday, April 26, 2021

Warp drives: Physicists give chances of faster-than-light space travel a boost

April 26, 2021 by Mario Borunda

Faster than light travel is the only way humans could ever get to other stars in a reasonable amount of time. Credit: Les Bossinas/NASA/Wikimedia Commons

The closest star to Earth is Proxima Centauri. It is about 4.25 light-years away, or about 25 trillion miles (40 trillion km). The fastest ever spacecraft, the now- in-space Parker Solar Probe will reach a top speed of 450,000 mph. It would take just 20 seconds to go from Los Angeles to New York City at that speed, but it would take the solar probe about 6,633 years to reach Earth's nearest neighboring solar system.

If humanity ever wants to travel easily between stars, people will need to go faster than light. But so far, faster-than-light travel is possible only in science fiction.

In Issac Asimov's Foundation series, humanity can travel from planet to planet, star to star or across the universe using jump drives. As a kid, I read as many of those stories as I could get my hands on. I am now a theoretical physicist and study nanotechnology, but I am still fascinated by the ways humanity could one day travel in space.

Some characters—like the astronauts in the movies "Interstellar" and "Thor"—use wormholes to travel between solar systems in seconds. Another approach—familiar to "Star Trek" fans—is warp drive technology. Warp drives are theoretically possible if still far-fetched technology. Two recent papers made headlines in March when researchers claimed to have overcome one of the many challenges that stand between the theory of warp drives and reality.

But how do these theoretical warp drives really work? And will humans be making the jump to warp speed anytime soon?

Compression and expansion

Physicists' current understanding of spacetime comes from Albert Einstein's theory of General Relativity. General Relativity states that space and time are fused and that nothing can travel faster than the speed of light. General relativity also describes how mass and energy warp spacetime—hefty objects like stars and black holes curve spacetime around them. This curvature is what you feel as gravity and why many spacefaring heroes worry about "getting stuck in" or "falling into" a gravity well. Early science fiction writers John Campbell and Asimov saw this warping as a way to skirt the speed limit.


This 2-dimensional representation shows the flat, unwarped bubble of spacetime in the center where a warp drive would sit surrounded by compressed spacetime to the right (downward curve) and expanded spacetime to the left (upward curve). 
Credit: Allen McC/Wikimedia Commons




What if a starship could compress space in front of it while expanding spacetime behind it? "Star Trek" took this idea and named it the warp drive.

In 1994, Miguel Alcubierre, a Mexican theoretical physicist, showed that compressing spacetime in front of the spaceship while expanding it behind was mathematically possible within the laws of General Relativity. So, what does that mean? Imagine the distance between two points is 10 meters (33 feet). If you are standing at point A and can travel one meter per second, it would take 10 seconds to get to point B. However, let's say you could somehow compress the space between you and point B so that the interval is now just one meter. Then, moving through spacetime at your maximum speed of one meter per second, you would be able to reach point B in about one second. In theory, this approach does not contradict the laws of relativity since you are not moving faster than light in the space around you. Alcubierre showed that the warp drive from "Star Trek" was in fact theoretically possible.

Proxima Centauri here we come, right? Unfortunately, Alcubierre's method of compressing spacetime had one problem: it requires negative energy or negative mass.

A negative energy problem

Alcubierre's warp drive would work by creating a bubble of flat spacetime around the spaceship and curving spacetime around that bubble to reduce distances. The warp drive would require either negative mass—a theorized type of matter—or a ring of negative energy density to work. Physicists have never observed negative mass, so that leaves negative energy as the only option.

To create negative energy, a warp drive would use a huge amount of mass to create an imbalance between particles and antiparticles. For example, if an electron and an antielectron appear near the warp drive, one of the particles would get trapped by the mass and this results in an imbalance. This imbalance results in negative energy density. Alcubierre's warp drive would use this negative energy to create the spacetime bubble.

But for a warp drive to generate enough negative energy, you would need a lot of matter. Alcubierre estimated that a warp drive with a 100-meter bubble would require the mass of the entire visible universe.

In 1999, physicist Chris Van Den Broeck showed that expanding the volume inside the bubble but keeping the surface area constant would reduce the energy requirements significantly, to just about the mass of the sun. A significant improvement, but still far beyond all practical possibilities.

This 2–dimensional representation shows how positive mass curves spacetime (left side, blue earth) and negative mass curves spacetime in an opposite direction (right side, red earth). 
Credit: Tokamac/Wikimedia Commons, CC BY-SA


A sci-fi future?

Two recent papers—one by Alexey Bobrick and Gianni Martire and another by Erik Lentz—provide solutions that seem to bring warp drives closer to reality.

Bobrick and Martire realized that by modifying spacetime within the bubble in a certain way, they could remove the need to use negative energy. This solution, though, does not produce a warp drive that can go faster than light.

Independently, Lentz also proposed a solution that does not require negative energy. He used a different geometric approach to solve the equations of General Relativity, and by doing so, he found that a warp drive wouldn't need to use negative energy. Lentz's solution would allow the bubble to travel faster than the speed of light.

It is essential to point out that these exciting developments are mathematical models. As a physicist, I won't fully trust models until we have experimental proof. Yet, the science of warp drives is coming into view. As a science fiction fan, I welcome all this innovative thinking. In the words of Captain Picard, things are only impossible until they are not.

This article is republished from The Conversation under a Creative Commons license. 


Recommend this post and follow
Sputnik's Orbit



Posted by Chuck  at warp speed.
Posted by on No comments:

Sunday, April 25, 2021

IAI and Thales Combine to Offer Next Generation Ship-Killing Solution for the Royal Navy

13.04.2021


Israel Aerospace Industries (IAI) and THALES in the UK have joined forces to offer SEA SERPENT as a compelling solution to equip the Royal Navy’s Type 23 frigates with an anti-ship and anti-surface missile that can match and overmatch a rapidly expanding range and intensity of current and emerging threats.

The SEA SERPENT delivers an agile, highly penetrative, combined anti-ship and land attack capability at ranges significantly in excess of 200 km. It deploys an innovative RF seeker head and a sophisticated data analysis and weapon control system to provide precise target detection, discrimination and classification.

 It overcomes both kinetic counter-fire and electronic countermeasures of increasing sophistication, so that the missile can locate and attack its target in littoral, open-ocean and overland environments. 
It is especially designed to prevail in contested, congested and confusing situations characterised by large numbers of decoys, disrupted reality and heavy electronic interference, as well as clutter from land and false returns. In fast-moving situations, SEA SERPENT incorporates mid-course updates from real-time ISTAR feeds and the ability to re-task in flight, especially in cooperative engagements and distributed sensor-and-shooter networks.

As the most advanced ship-launched anti-surface missile in the free world, SEA SERPENT also offers significant Military Off-the-Shelf Solution (MOTS) advantages in terms of cost, time-to-procurement, entry into operational service and risk reduction. Benchmarked against the need to defeat the most sophisticated platforms and technologies, SEA SERPENT has been developed in parallel with similar missile systems in service with the Israeli Navy and was selected to provide powerful strike capabilities for Finland’s SSM2020 programme. These systems are based on the heritage of the GABRIEL family of surface-to-surface missiles. SEA SERPENT has already demonstrated an impressive Next Day capacity to deal with emerging threats, as well as the technological flexibility for further growth and development.

IAI looks forward to partnering with THALES in the UK’s proven track record of delivering complex sensor and weapon solutions for the Royal Navy and other navies.

Both companies are fully committed to maximising UK prosperity and creating employment and investment opportunities. The IAI/THALES in the UK solution for SEA SERPENT will concentrate on utilising UK industry content and expertise for initial delivery, through-life maintenance and support, as well as future development and upgrade options.


Recommend this post and follow
Sputnik's Orbit


Posted by on No comments:

Saturday, April 24, 2021

Scientists propose new formation mechanism for solar coronal rain

APRIL 22, 2021, by Chinese Academy of Sciences

Flare-driven coronal rain observed by AIA on board the SDO. 
Credit: NASA/SDO/Goddard Scientific Visualization Studio

Rain is a common phenomenon on Earth. There is a similar phenomenon on the Sun, called coronal rain. It is related to the coronal heating and magnetic field, and plays a fundamental role in the mass cycle between the hot, tenuous corona and the cool, dense chromosphere.

Coronal rain usually takes place in post-flare loops and the non-flaring active region coronal loops. It is generally classified into two categories: flare-driven and quiescent coronal rain, depending on its relation to the flare. Both kinds of coronal rain form along structures that are magnetically closed.

Recently, a research team led by Dr. Li Leping from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) found a new type of coronal rain forming along open magnetic structures, away from the magnetically closed region.

A series of studies has been issued since 2018, among which the latest paper was published in The Astrophysical Journal on April 1.

The researchers proposed a new formation mechanism for coronal rain along open magnetic structures facilitated by interchange magnetic reconnection between open and closed magnetic structures.

In this formation mechanism, the higher-lying open structures reconnect with the lower-lying closed loops, forming a magnetic dip in the former. The plasma, surrounding the dip, converges into the dip, resulting in the enhancement of plasma density in the dip. The density enhancement triggers thermal instability. Cooling and condensation of hot coronal plasma in the dip thus occurs. The cool condensation falls toward the solar surface as coronal rain.

Schematic diagrams of coronal condensation facilitated by interchange magnetic reconnection between open and closed magnetic structures observed from three vantage points 
Credit: Li Leping




No flare was detected during the reconnection and condensation process. The new type of coronal rain thus belongs to the category of quiescent coronal rain.

"The quiescent coronal rain forming along the open structures is quite different from the flare-driven coronal rain in post-flare loops and the quiescent coronal rain in non-flaring active region loops that occur in the closed loops," said Dr. Li Leping, the first author of the series of studies.

All the reconnection and condensation events investigated before took place above the limb.

"Whether the condensation facilitated by reconnection can still be observed on the disk, and how it performs, are open questions," said Prof. Hardi Peter from the Max Planck Institute for Solar System Research (MPS), a co-author of the series of studies.

The researchers found that the reconnection condensation events from September 2010-September 2011, observed above the eastern (western) limb of the Solar Terrestrial Relations Observatory (STEREO A (B)), occurred on the disk of the Solar Dynamics Observatory (SDO).

"The event presented is important for understanding the global picture of condensation formation in the solar atmosphere and the combined observations bring a very interesting means to analyze this type of coronal condensation events," the reviewer of the paper commented.

Above the limb, the bright condensations and the subsequent coronal rain, facilitated by reconnection between open and closed structures, were clearly detected. However, on the disk, the reconnection structures were difficult to observe. Moreover, dark condensations appeared and moved to the surface as on-disk coronal rain.

"If only the on-disk observations are available, the relation between the condensations and reconnection, shown clearly by the off-limb observations, could not be identified," said Dr. Li. "We propose that some on-disk condensation events seen in the transition region and chromospheric lines could be facilitated by interchange reconnection."


Recommend this post and follow
Sputnik's Orbit



Posted by on No comments:

Thursday, April 22, 2021

Humongous flare from sun's nearest neighbor breaks records

APRIL 21, 2021, by Daniel Strain, University of Colorado at Boulder

Artist's conception of the violent stellar flare from Proxima Centauri discovered by scientists in 2019 using nine telescopes across the electromagnetic spectrum, including the Atacama Large Millimeter/submillimeter Array (ALMA). 
Powerful flares eject from Proxima Centauri with regularity, impacting the star's planets almost daily. 
Credit: NRAO/S. Dagnello

Scientists have spotted the largest flare ever recorded from the sun's nearest neighbor, the star Proxima Centauri.

The research, which appears today in The Astrophysical Journal Letters, was led by the University of Colorado Boulder and could help to shape the hunt for life beyond Earth's solar system.

CU Boulder astrophysicist Meredith MacGregor explained that Proxima Centauri is a small but mighty star. It sits just four light-years or more than 20 trillion miles from our own sun and hosts at least two planets, one of which may look something like Earth. It's also a red dwarf, the name for a class of stars that are unusually petite and dim.

Proxima Centauri has roughly one-eighth the mass of our own sun. But don't let that fool you.

In their new study, MacGregor and her colleagues observed Proxima Centauri for 40 hours using nine telescopes on the ground and in space. In the process, they got a surprise: Proxima Centauri ejected a flare, or a burst of radiation that begins near the surface of a star, that ranks as one of the most violent seen anywhere in the galaxy.

"The star went from normal to 14,000 times brighter when seen in ultraviolet wavelengths over the span of a few seconds," said MacGregor, an assistant professor at the Center for Astrophysics and Space Astronomy (CASA) and Department of Astrophysical and Planetary Sciences (APS) at CU Boulder.

The team's findings hint at new physics that could change the way scientists think about stellar flares. They also don't bode well for any squishy organism brave enough to live near the volatile star.

"If there was life on the planet nearest to Proxima Centauri, it would have to look very different than anything on Earth," MacGregor said. "A human being on this planet would have a bad time."

Active stars

The star has long been a target for scientists hoping to find life beyond Earth's solar system. Proxima Centauri is nearby, for a start. It also hosts one planet, designated Proxima Centauri b, that resides in what researchers call the habitable zone—a region around a star that has the right range of temperatures for harboring liquid water on the surface of a planet.

But there's a twist, MacGregor said: Red dwarves, which rank as the most common stars in the galaxy, are also unusually lively.

"A lot of the exoplanets that we've found so far are around these types of stars," she said. "But the catch is that they're way more active than our sun. They flare much more frequently and intensely."

Artist's conception of a violent stellar flare erupting on neighboring star, Proxima Centauri. The flare is the most powerful ever recorded from the star, and is giving scientists insight into the hunt for life in M dwarf star systems, many of which have unusually lively stars. Artist's conception of a violent stellar flare erupting on neighboring star, Proxima Centauri. The flare is the most powerful ever recorded from the star, and is giving scientists insight into the hunt for life in M dwarf star systems, many of which have unusually lively stars. 
Credit: NRAO/S. Dagnello

To see just how much Proxima Centauri flares, she and her colleagues pulled off what approaches a coup in the field of astrophysics: They pointed nine different instruments at the star for 40 hours over the course of several months in 2019. Those eyes included the Hubble Space Telescope, the Atacama Large Millimeter Array (ALMA) and NASA's Transiting Exoplanet Survey Satellite (TESS). Five of them recorded the massive flare from Proxima Centauri, capturing the event as it produced a wide spectrum of radiation.

"It's the first time we've ever had this kind of multi-wavelength coverage of a stellar flare," MacGregor said. "Usually, you're lucky if you can get two instruments."

Crispy planet

The technique delivered one of the most in-depth anatomies of a flare from any star in the galaxy.

The event in question was observed on May 1, 2019 and lasted just 7 seconds. While it didn't produce a lot of visible light, it generated a huge surge in both ultraviolet and radio, or "millimeter," radiation.

"In the past, we didn't know that stars could flare in the millimeter range, so this is the first time we have gone looking for millimeter flares," MacGregor said.

Those millimeter signals, MacGregor added, could help researchers gather more information about how stars generate flares. Currently, scientists suspect that these bursts of energy occur when magnetic fields near a star's surface twist and snap with explosive consequences.

In all, the observed flare was roughly 100 times more powerful than any similar flare seen from Earth's sun. Over time, such energy can strip away a planet's atmosphere and even expose life forms to deadly radiation.

That type of flare may not be a rare occurrence on Proxima Centauri. In addition to the big boom in May 2019, the researchers recorded many other flares during the 40 hours they spent watching the star.

"Proxima Centauri's planets are getting hit by something like this not once in a century, but at least once a day if not several times a day," MacGregor said.

The findings suggest that there may be more surprises in store from the sun's closest companion.

"There will probably be even more weird types of flares that demonstrate different types of physics that we haven't thought about before," MacGregor said.


Recommend this post and follow 
Sputnik's Orbit


Posted by Chuck in Space


Posted by on No comments:
Subscribe to: Posts (Atom)