Large Hardon Collider

[Kryssan]

Been busy with work, so falling behind. Some interesting stuffs in March.


This article is really just a quick look into some of the equipment used and the stresses they undergo: Fusion getting hot, hot, hot


Here's a tech article, this one for the ITER project: Packing a punch


Crossposted:

There's an electromagnet in the centre of the ITER Tokamak - thirteen metres tall, four metres wide and one thousand tons - that has been designed to pack a terrific punch.

The ITER Central Solenoid (CS) will take advantage of every bit of space from its central position in the machine - right up to the ten millimetres of radial clearance it shares with the surrounding toroidal field magnet system - to achieve the highest value of stored magnetic energy possible.

The central solenoid is the key component that will allow a powerful current to be induced in the ITER plasma and maintained during long plasma pulses.

Two parameters that are important to obtaining maximum plasma current drive are magnetic field and the area of the solenoid. The higher the magnetic field and the larger the area of the magnet where it exists, the greater the magnetic flux, the quantity that characterizes current drive capability.

The ITER Central Solenoid (CS) - with a diameter of 4,3 metres and a height of 13 metres - will top the charts as the largest solenoid ever built for a fusion device. Maximum field of 13 tesla will be reached in the centre of the CS. That's the strongest of all ITER magnet systems, and equivalent to 280 000 times the magnetic field of the Earth.

Solenoids are lengths of coiled wire that generate magnetic fields when electric current is passed through them. Electricity and magnetism are closely related: place two solenoids one inside the other, and the variation of electrical current in the first will produce a variation of electrical current in the second.

ITER and other tokamaks essentially act as large transformers, where the central solenoid is the primary winding, and the plasma the secondary winding.

Solenoids are responsible for driving the plasma current in all tokamak devices. At the largest currently-operating tokamak (JET in the UK), the solenoid initiates plasma currents of about 5 megaamperes (MA) for plasma pulses lasting up to 60 seconds. The plasma volume in ITER will be eight times greater than in JET, and consequently the "drive" required from the central solenoid will be much greater as well. Stored magnetic energy of 6,4 GJ in the central solenoid will initiate and sustain a plasma current of 15 MA for durations of 300-500 seconds.

But the role of the central solenoid doesn't end there. As the high-intensity current circulates within the tokamak, electrons and ions in the plasma will become energized and collide. Collisions create 'resistance' that produces heat. This heating effect, known as ohmic heating, will contribute to bringing the ITER plasma to the temperatures close to 150 million degrees Celsius necessary for fusion to take place.

The central solenoid will also assist in shaping the plasma. Physicists prefer a D-shaped plasma to a circular one; by 'tweaking' current applied to the top and bottom central solenoid modules (see below), operators will use variations in magnetic field to elongate the cross section of the ITER plasma and achieve this optimum shape.

The "central" solenoid is indeed central to the success of ITER operation. Its combination of performance parameters makes it one of the most complex and challenging magnet systems ever built. Strong team effort will be required from all parties throughout the design, fabrication and assembly process.

The "electrical ballet" of the central solenoid

In order to induce powerful current in the plasma, the ITER Central Solenoid will have to carry a lot of current - 46 kA to be precise.

During "ramp-up" at the beginning of an experiment in ITER, voltage will be applied to the six central solenoid modules until they each reach 40 kA of current. This "pre-magnetization' period will last for approximately six minutes.

The current will then be discharged to initiate a plasma pulse. From this moment - until the end of the cycle - the six central solenoid modules will act independently, each following an individual current profile. In certain modules, current will drop to zero directly, before being ramped up again in the reverse direction; others will decrease more progressively; still others will change current directions twice. Only the two central modules, CS1U and CS1L, act as a pair. Toward the end of the cycle, maximum current of 46 kA is reached in some modules.

These variations in current between the different modules give scientists the tool they need for plasma shaping. Current variation, which induces magnetic flux variation, is the key to producing the large plasma current needed for ITER. "What we want in ITER," says Paul Libeyre, Central Solenoid and Correction Coil Section Leader, "is maximum flux variation to allow long plasma pulses."

A central solenoid with fixed current would never work. "Having the possibility of varying the current differently in each of the six modules allows a lot of different scenarios," Paul explains. "It's like allowing dancers to perform individual choreographies, instead of marching all together like in a military parade."

Operators will also use current variation in the top and bottom modules to influence the shape of the plasma for best performance.

For the duration of each 1 000 second plasma pulse during ITER operation, the ballet of increasing and decreasing voltage will continue in the modules, carefully choreographed to build the plasma current up to a plateau of 15 MA for around 400 seconds, before ramping down again to zero.

30 000 plasma pulses are foreseen for the ITER experimental campaign, during which the central solenoid will be "ramped up" to initiate plasma current and "ramped down" again at the end of each pulse.

Another tech article from about uranium enrichment technologies currently being developed for production use. The idea isn't new, but its never been employed. The article is here but since they don't really explain what they're doing, this is from the description of USEC, Inc.

[Mizango]

Really neat article I ran across this morning. All I can say is holy cow. I know the initial report isnt that mind blowing but I think its a step in the right direction at least and opens up a door to all sorts of possibilities.

http://www.scientificamerican.com/ar...tum-microphone

PORTLAND, Ore.—What's the sound of one molecule clapping? Researchers have demonstrated a device that can pick up single quanta of mechanical vibration similar to those that shake molecules during chemical reactions, and have shown that the device itself, which is the width of a hair, acts as if it exists in two places at once—a "quantum weirdness" feat that so far had only been observed at the scale of molecules.

"This is a milestone," says Wojciech Zurek, a theorist at the Los Alamos National Laboratory in New Mexico. "It confirms what many of us believe, but some continue to resist—that our universe is 'quantum to the core'."

Physicists have long known that, following the laws of quantum mechanics, objects at the scale of atoms or smaller can exist in multiple simultaneous states. For example, a single electron can move along multiple different paths or an atom can be placed in two different places, simultaneously. This so-called superposition of states should in principle apply to larger objects, as well, as in the proverbial thought experiment in which a cat is simultaneously dead and alive. And in recent years various teams have shown that the weird phenomenon does occur among objects as big as molecules, and also in truly macroscopic systems such as electrical currents in superconductors.

In the new experiment Aaron O'Connell, a graduate student at the University of California, Santa Barbara, and his co-workers have shown for the first time that larger objects can also be in two places at once. "It tells us that quantum mechanics works for macroscopic objects in space," says O'Connell, who presented the results here at a meeting of the American Physical Society. The results were also published online Wednesday in Nature. (Scientific American is part of Nature Publishing Group.)

The team used computer-chip manufacturing techniques to create a mechanical resonator—akin to a small tuning fork. The device is a piece of piezoelectric material (a material that expands or contracts in the presence of an electric field as well as generates an electrical field when put under stress) sandwiched between two layers of aluminum, which act as electrodes. It is one micron thick and 40 microns long, just enough to be visible "with your naked eye," O'Connell says.

The resonator's electrodes are attached to an electronic readout based on superconducting circuits, and the whole contraption is kept in a vacuum and cooled to within 20 thousandths of a degree above absolute zero. But the electronic circuitry can also be used to apply a voltage to the electrodes, so that the team can get the resonator to expand and contract at will. This motion takes place at a characteristic, or resonant, frequency of six gigahertz, or six billion cycles per second. (Tuning forks also have a resonant frequency—in the order of kilohertz—but the mode of resonant vibration in that case is to oscillate sideways rather than to expand and contract.)

The team's first result was to show that at such chilly temperatures the width, or amplitude, of the resonator's vibration becomes quantized—in other words, there is a small amount of vibrational energy, called a phonon, below which the resonator is essentially still. The existence of discrete packets of energy is a hallmark of quantum behavior, and phonons are the mechanical equivalent of light's photons—they are the ultimate, indivisible quanta of vibration, whether thermal or acoustic.

Next, the team put the superconducting circuit into a superposition of two states, one with a current and the other one without. Correspondingly, the resonator was in a superposition of vibrating and not vibrating. These quantum states continued for about six nanoseconds—about as long as the team expected—before fading away.

In a vibrating state each atom in the resonator only moves by an extremely small distance—less than the size of the atom itself. Thus, in the superposition of states the resonator is never really in two totally distinct places. But still, the experiment showed that a large object (the resonator is made of about 10 trillion atoms) can display just as much quantum weirdness as single atoms do. "Yup, quantum mechanics still works," says U.C.S.B.'s Andrew Cleland, O'Connell's co-author and adviser. As to how the day-to-day reality of objects that we observe, such as furniture and fruit, emerges from such a different and exotic quantum world, that remains a mystery.

In addition to its theoretical implications, the device could also find applications in the study of phonons that occur in nature, because a phonon that perturbs the resonator can be detected through the electronic circuit—it is essentially a quantum microphone. "This is a fantastically sensitive detector of acoustic vibration," Cleland says. In principle, one could even place molecules on the resonator and "hear them" interact, chemically or otherwise.

[Eliseos]

But can this contraption make me coffee in the morning?

Also, XKCD today was awesome:

http://imgs.xkcd.com/comics/time_machine.png

[Tristam]

Yesssssssssss. I need to see this.

http://www.youtube.com/watch?v=4pQQJ...layer_embedded

[Mizango]

Yesssssssssss. I need to see this.

http://www.youtube.com/watch?v=4pQQJ...layer_embedded

Oh god yes.

[Max™]

10 trillion atoms is hardly a large object... I'm still awaiting tests of Penrose's planck mass -> decoherence conjecture, I wonder how much that experiment can be scaled up?

Also: fuck yes, I need to go find the Imax here in Memphis when it comes out.

[Max™]

Ba-bump for news!

http://press.web.cern.ch/press/Press.../PR05.10E.html

3.5 TeV!

[Woozie]

Saw this at work today, thought it was pretty interesting

http://www.scientificamerican.com/ar...ames-webb-jwst

EDIT: URL not working right because of the = sign in it, article title is 6 Fun Facts about the James Webb Space Telescope. Neat pictures of it and the development.

One of those slides scares me:

ONE SHOT TO GET IT RIGHT (MAYBE)

Hubble's life has been extended time and again through five servicing missions in which space shuttle astronauts have fixed faulty components, upgraded instrumentation and replaced batteries. The first such mission [pictured] was an absolute necessity; Hubble's mirror was malformed, causing optical problems that crippled the telescope until astronauts could fix it. But no human has ever traveled as far as sun–Earth L2, so at the moment a servicing mission to JWST is out of the question. "It does inform us that it has to work," Arenberg said. It is imperative that the engineers "avoid a Hubble-like mistake, because we will have no chance to recover," Arenberg added.

Nevertheless, the designers have been instructed to study the hypothetical addition of a grapple point, which an as-yet undeveloped deep-space vehicle might use to dock with JWST, assuming the telescope survived long enough for such a mission to become possible. (The telescope's baseline mission is five years, but Arenberg expects that it will last much longer.) "If some astronaut who is in nursery school right now wants to go up there and fix it, they'd be able to," Arenberg said.

Think of how much we had to fix up the hubble.......we don't even have the option to fix this one. So everything has to go perfectly or we're screwed. How much did this thing cost again?

Really neat article I ran across this morning. All I can say is holy cow. I know the initial report isnt that mind blowing but I think its a step in the right direction at least and opens up a door to all sorts of possibilities.

http://www.scientificamerican.com/ar...tum-microphone

Now this is some amazing stuff here. How is it that when I got one week without checking SciAm a bunch of good stuff pops up? Normally I can check the site only once per month and not miss too much. It's been hard for me to check anything on the internet lately because I somehow injured my shoulder without even doing any physical activity. I must have been attacked by a ghost or something, because the pain came out of nowhere. But it hurts so bad that I can't type or move the mouse on my computer around for more than 5 or 10 minutes at a time before it becomes too painful.

[Mizango]

I know man, it always happens that way lol.

[Woozie]

By the way, the march issues of SciAm and NewScientist are up on demonoid.

http://i40.tinypic.com/p37ms.jpg

http://i41.tinypic.com/333h64l.jpg

and

http://i45.tinypic.com/rlddhi.jpg

Are all up on demonoid. The first and the last look like stuff Miz be interested in, since you're the astronomy/astrophysics/cosmology guy. I haven't read them yet, since, like I said, I can't sit at the computer for more than 5~10 minutes straight.

Edit: Video talking about the article

http://www.newscientist.com/articlev...inal-test.html

The video doesn't really say anything you probably don't already know, Miz. But the article seems interesting from what I've read so far (article says more than the video).

Edit 2: By the way, when do you start working on your cosmetology cosmology degree, Miz? Have you started already? And do you have any idea what specifically you want to study?

[Mizango]

Awesome!

[Mizango]

Yes, I started in September, I go after I get off of work which is why I am on during the mornings but once 2 oclock or so comes I am usually not on until the next day or much much later at night

[Mizango]

I love every minute of it. brb downloading!

Edit: I just noticed the Cosmetology edit you did HAHA XD

[Woozie]

How long will it take you to finish? And do you have a specific area of research in mind? Like a specific subject or project you'll be writing your thesis or dissertation on? I'm still not sure what I'm going to write my thesis on for my Math masters @_@. I still have plenty of time though. It will probably be something analysis-related, but other than that I don't really have a clue what it's going to be on yet.

Edit: By the way, I got accepted to a summer REU today. There was an option to study dark matter, but I decided to go to something called Josephson Junctions because the math looks more fun/interesting.

http://reu.owu.edu/projectDescriptions.html

The dark matter stuff doesn't really look that interesting here. It's probably because all of the interesting stuff requires a lot more than what they would expect from undergrads physics majors. The Josephson Junctions (the first project described) is the group I'll be in.

[Eliseos]

If this was an article on yahoo, I would probably have not shared it. But since it's on SD, I think at least Kryssan would find it interesting:

http://www.sciencedaily.com/releases...0321182909.htm

ScienceDaily (Mar. 22, 2010) — A potential new energy source so controversial that people once regarded it as junk science is moving closer to acceptance by the mainstream scientific community. That's the conclusion of the organizer of one of the largest scientific sessions on the topic -- "cold fusion" -- being held here for the next two days in the Moscone Center during the 239th National Meeting of the American Chemical Society (ACS).

"Years ago, many scientists were afraid to speak about 'cold fusion' to a mainstream audience," said Jan Marwan, Ph.D., the internationally known expert who organized the symposium. Marwan heads the research firm, Dr. Marwan Chemie in Berlin, Germany. Entitled "New Energy Technology," the symposium will include nearly 50 presentations describing the latest discoveries on the topic.

The presentations describe invention of an inexpensive new measuring device that could enable more labs to begin cold fusion research; indications that cold fusion may occur naturally in certain bacteria; progress toward a battery based on cold fusion; and a range of other topics. Marwan noted that many of the presentations suggest that cold fusion is real, with a potential to contribute to energy supplies in the 21st Century.

"Now most of the scientists are no longer afraid and most of the cold fusion researchers are attracted to the ACS meeting," Marwan said. "I've also noticed that the field is gaining new researchers from universities that had previously not pursued cold fusion research. More and more people are becoming interested in it. There's still some resistance to this field. But we just have to keep on as we have done so far, exploring cold fusion step by step, and that will make it a successful alternative energy source. With time and patience, I'm really optimistic we can do this!"

The term "cold fusion" originated in 1989 when Martin Fleishmann and Stanley Pons claimed achieving nuclear fusion at room temperature with a simple, inexpensive tabletop device. That claim fomented an international sensation because nuclear fusion holds potential for providing the world with a virtually limitless new source of energy. Fuel for fusion comes from ordinary seawater, and estimates indicate that 1 gallon of seawater packs the energy equivalent of 16 gallons of gasoline at 100 percent efficiency for energy production. The claim also ignited scepticism, because conventional wisdom said that achieving fusion required multi-billion-dollar fusion reactors that operate at tens of millions of degrees Fahrenheit.

When other scientists could not reproduce the Pons-Fleishmann results, research on cold fusion fell into disrepute. Humiliated by the scientific establishment, their reputations ruined, Pons and Fleishmann closed their labs, fled the country, and dropped out of sight. The handful of scientists who continued research avoided the term "cold fusion." Instead, they used the term "low energy nuclear reactions (LENR)." Research papers at the ACS symposium openly refer to "cold fusion" and some describe cold fusion as the "Fleishmann-Pons Effect" in honor of the pioneers, Marwan noted.

"The field is now experiencing a rebirth in research efforts and interest, with evidence suggesting that cold fusion may be a reality." Marwan said. He noted, for instance, that the number of presentations on the topic at ACS National Meetings has quadrupled since 2007.

Among the reports scheduled for the symposium are:

* Michael McKubre, Ph.D., of SRI International in Menlo Park, Calif., provides an overview of cold fusion research. McKubre will discuss current knowledge in the field and explain why some doubts exist in the broader scientific community. He will also discuss recent experimental work performed at SRI. McKubre will focus on fusion, heat production and nuclear products. [3pm, Monday March 22, Cyril Magnin ]
* George Miley, Ph.D., reports on progress toward a new type of battery that works through a new cold fusion process and has a longer life than conventional batteries. The battery consists of a special type of electrolytic cell that operates at low temperature. The process involves purposely creating defects in the metal electrode of the cell. Miley is a professor at the University of Illinois in Urbana and director of its Fusion Studies Lab. [11am, Sunday March 21, Cyril Magnin I]
* Melvin Miles, Ph.D., describes development of the first inexpensive instrument for reliably identifying the hallmark of cold fusion reactions: Production of excess heat from tabletop fusion devices now in use. Current "calorimeters," devices that measure excess heat, tend to be too complicated and inefficient for reliable use. The new calorimeter could boost the quality of research and open the field to scores of new scientists in university, government, and private labs, Miles suggests. He is with Dixie State College in St. George, Utah. [2.30pm, Sunday March 21, Cyril Magnin I]
* Vladimir Vysotskii, Ph.D., presents surprising experimental evidence that bacteria can undergo a type of cold fusion process and could be used to dispose of nuclear waste. He will describe studies of nuclear transmutation -- the transformation of one element into another -- of stable and radioactive isotopes in biological systems. Vysotskii is a scientist with Kiev National Shevchenko University in Kiev, Ukraine. [11.20am, Monday March 22, Cyril Magnin I].
* Tadahiko Mizuno, Ph.D., discusses an unconventional cold fusion device that uses phenanthrene, a substance found in coal and oil, as a reactant. He reports on excess heat production and gamma radiation production from the device. "Overall heat production exceeded any conceivable chemical reaction by two orders of magnitude," Mizuno noted. He is with Hokkaido University in Japan, and wrote the book Nuclear Transmutation: The Reality of Cold Fusion. [3pm, Sunday March 21, Cyril Magnin I]
* Peter Hagelstein, Ph.D., describes new theoretical models to help explain excess heat production in cold fusion, one of the most controversial aspects of the field. He notes that in a nuclear reaction, one would expect that the energy produced would appear as kinetic energy in the products, but in the Fleischmann-Pons experiment there do not appear energetic particles in amounts consistent with the energy observed. His simple models help explain the observed energy changes, including the type and quantity of energy produced. Hagelstein is with the Massachusetts Institute of Technology. [10.20am, Sunday March 21, Cyril Magnin I].
* Xing Zhong Li, Ph.D., presents research demonstrating that cold fusion can occur without the production of strong nuclear radiation. He is developing a cold fusion reactor that demonstrates this principle. Li is a scientist with Tsinghua University in Beijing, China. [9.10am, Sunday March 21, Cyril Magnin I].

[Kryssan]

I'm still withholding judgement.



I have to admit that I am one of those people that at the mention of the words 'cold fusion' I think of those two names and the bile rises quickly. Its a sore topic that won't go away anytime soon. Not without someone actually proving something this time and not being media whores.




Only takes one or two idiots to ruin it for everyone.

[Eliseos]

Yeah, I'm not too sold on it either. At least this time around it is getting more of a scientific method approach.

[Woozie]

Every time I hear the word "cold fusion", I look for a kitten to strangle.

[Max™]

If you compress a kitten properly, you can initiate cold fusion.

[Mizango]

I hear Schrödinger may or may not have a few kittens for you to strangle.