NASA is trying to figure out why when magnetic field lines containing charged particles cross on the sun, things go “boom”. In earth’s magnetic field, we get “magnetic portals” to the sun. Sounds like a movie.
From NASA Science News
August 31, 2009: Magnetic reconnection could be the Universe’s favorite way to make things explode. It operates anywhere magnetic fields pervade space–which is to say almost everywhere. On the sun magnetic reconnection causes solar flares as powerful as a billion atomic bombs. In Earth’s atmosphere, it fuels magnetic storms and auroras. In laboratories, it can cause big problems in fusion reactors. It’s ubiquitous.
The problem is, researchers can’t explain it.
The basics are clear enough. Magnetic lines of force cross, cancel, reconnect and—Bang! Magnetic energy is unleashed in the form of heat and charged-particle kinetic energy.
Right: A cartoon model of magnetic reconnection on the sun. [more]
But how? How does the simple act of crisscrossing magnetic field lines trigger such a ferocious explosion?
“Something very interesting and fundamental is going on that we don’t really understand — not from laboratory experiments or from simulations,” says Melvyn Goldstein, chief of the Geospace Physics Laboratory at NASA’s Goddard Space Flight Center.
NASA is going to launch a mission to get to the bottom of the mystery. It’s called MMS, short for Magnetospheric Multiscale Mission, and it consists of four spacecraft which will fly through Earth’s magnetosphere to study reconnection in action. The mission passed its preliminary design review in May 2009 and was approved for implementation in June 2009. Engineers can now start building the spacecraft.
“Earth’s magnetosphere is a wonderful natural laboratory for studying reconnection,” says mission scientist Jim Burch of the Southwest Research Institute. “It is big, roomy, and reconnection is taking place there almost non-stop.”
In the outer layers of the magnetosphere, where Earth’s magnetic field meets the solar wind, reconnection events create temporary magnetic “portals” connecting Earth to the sun. Inside the magnetosphere, in a long drawn-out structure called “the magnetotail,” reconnection propels high-energy plasma clouds toward Earth, triggering Northern Lights when they hit. There are many other examples, and MMS will explore them all.
The four spacecraft will be built at the Goddard Space Flight Center. “Each observatory is shaped like a giant hockey puck, about 12 feet in diameter and 4 feet in height,” says Karen Halterman, MMS Project Manager at Goddard.
Above: An artist’s concept of the four MMS spacecraft flying in formation through the space around Earth. [more]
The mission’s sensors for monitoring electromagnetic fields and charged particles are being built at a number of universities and laboratories around the country, led by the Southwest Research Institute. When the instruments are done, they will be integrated into the spacecraft frames at Goddard. Launch is scheduled for 2014 onboard an Atlas V rocket.
Any new physics MMS learns could ultimately help alleviate the energy crisis on Earth.
“For many years, researchers have looked to fusion as a clean and abundant source of energy for our planet,” says Burch. “One approach, magnetic confinement fusion, has yielded very promising results with devices such as tokamaks. But there have been problems keeping the plasma (hot ionized gas) contained in the chamber.”
“One of the main problems is magnetic reconnection,” he continues. “A spectacular and even dangerous result of reconnection is known as the sawtooth crash. As the heat in the tokamak builds up, the electron temperature reaches a peak and then ‘crashes’ to a lower value, and some of the hot plasma escapes. This is caused by reconnection of the containment field.”
Right: Inside a tokamak. Image credit: Lawrence Berkeley Labs [more]
In light of this, you might suppose that tokamaks would be a good place to study reconnection. But no, says Burch. Reconnection in a tokamak happens in such a tiny volume, only a few millimeters wide, that it is very difficult to study. It is practically impossible to build sensors small enough to probe the reconnection zone.
Earth’s magnetosphere is much better. In the expansive magnetic bubble that surrounds our planet, the process plays out over volumes as large as tens of kilometers across. “We can fly spacecraft in and around it and get a good look at what’s going on,” he says.
That is what MMS will do: fly directly into the reconnection zone. The spacecraft are sturdy enough to withstand the energetics of reconnection events known to occur in Earth’s magnetosphere, so there is nothing standing in the way of a full two year mission of discovery.
Learn more about the mission at the MMS Home Page.
James F. Evans (08:47:08) :
Fabron (09:41:31) :
No initial magnetic field required, however appearance of the electric current will generate magnetic field.
You [and many others] have this wrong. The discussion is not whether currents generate magnetic fields, of course they do.
In non-conductors [e.g. our air] you need a battery to make a current which in turn creates a magnetic field. A battery is a device where there is an imbalance of charges between two sides of the battery. Unlike charges will move towards each other [a current] and after a while there is no imbalance any more, the battery is flat.
In a dilute, electrically neutral plasma such an imbalance cannot exist for long because the electromagnetic force is so strong: the charges will immediately discharge [the battery goes flat]. To maintain a current you need to continuously separate the charges [against their mutual extremely strong attraction]. A magnetic field is a good separating device: it deflects positive charges one way and negative charges the other way. In cosmical plasmas there is always a magnetic field. These are everywhere we have looked. The magnetic field separates the charges and you have a nice battery [that never goes flat as long as there are charges around] that drives the currents we see causing explosive reconnection events. Movements of the plasma can transport the magnetic field and enhance the separation effects by creating suitable magnetic configurations, e.g. pressing oppositely directed field lines together.
So, in the highly conducting cosmical plasmas that are always permeated by magnetic fields, those fields create the electric currents whose effect we see at times. This is very simple and has nothing to do with Maxwell, Einstein, Quantum Mechanics, or anything exotic.
I have studied magnetohydrodynamics, plasma physics, and astrophysics in my graduate education, which regrettably was too long ago for me to raise a banner and charge into the fray.
Nevertheless, I can side with those who point out the fundamental unreality of magnetic field “lines.” Such lines are only an intellectual construct; the reality is the continuous magnetic field, which is a vector field. A useful metaphor would be the elevation contour lines on a topographic map. The underlying reality is the terrain. There are no “connecting” or “crossing” contours. There may be inflection or “saddle” regions in the field where “lines” can appear to cross, but the understanding that they are really mirror images is the truth. Finally, it is true that an earthquake can rearrange the elevation contour lines of a given terrain. But it is untrue that the contour lines can rearrange the terrain to cause an earthquake.
Behavior of magnetic fields in a plasma is alien to most of our life experience, because the fields are immersed in a medium that interacts with both magnetic and electric fields. This does not justify magical explanations, however.
A very interesting alternative view of the energy transport mechanisms of the Sun has been advanced by Laszlo Kortvelyessy (http://www.the-electric-universe.info/welcome.html).
Michael J. Dunn (11:59:08) :
There may be inflection or “saddle” regions in the field where “lines” can appear to cross
One should not take the simple field line pictures as literal truth. They are mental constructs that help organize the topology of the field. At the ‘crossing’ point very strong currents are induced by the changing magnetic field and those currents have a magnetic field too that helps change the topology. There is no magic. On the other hand, most astrophysicists take an operational view on field lines, in the sense that they are what are traced out by a small charged test particle. We can for example in interplanetary space see electrons spiraling around a ‘field line’ all the way back to the Sun and use the electrons to ‘label’ a field line. Many problems arise when people begin to take the mental constructs we make and find useful too literally, e.g. a nucleus with its attendant electron orbitals is often depicted as miniature solar system. This is but a crude picture, but is at times useful [and at others not].
Brownian motion begat plasma (?)( lsvalgaard vs. vukcevic):
Ordinary particles without charge in Brownian motion move in random directions, charge particles do not, there is such thing as critical distance regulated by forces of attraction and repulsion. Collisions of charged particles in plasmas are quite different from normal neutral particle collisions. Neutral particles move independently along straight-line trajectories between distinct collision events, which are typically strong, inelastic events that cause the neutral particle to be scattered in approximately random direction. In contrast, a charged particle moving through a plasma simultaneously experiences (and is deflected by) the weak Coulomb electric field forces around all the nearby charged particles as it passes by each of them. Since the electric fields around the individual charged particles are quite weak and Coulomb collisions are elastic (energy-conserving), they individually lead to typically only very small deflections in the direction of motion Thus, the trajectory of a charged particle is influenced by many simultaneous, small angle deflections in its direction of motion.
Further more, as mentioned above, in one of his first major theoretical works Einstein has shown in 1905 that Brownian motion on the atomic and molecular scale is a function of the particles’ size. From the above arise important consequence as far as plasma is concerned. The localised magnetic field arising from initial micro-currents (on an atomic scale), will exert certain amount of a feedback on the original particles’ Brownian motion, bringing more orderly flow to the electrical charges, in turn producing even stronger currents and magnetic fields, until eventually plasma is turned into orderly, collisionless multi layered flow. The magnetic field so created, may appear to be a frozen field carried by plasma, but in reality is a result of number of factors brought into steady orderly state by electro & magnetic feedback. Further more, it may be assumed that under such condition an outward orderly expansion of plasma gas is imperative as it is propelled by electric charge – magnetic field interaction.
Gravity force may impede on this self propulsion, but as gravitation weakens plasma flow will accelerate. This is one of the properties of the solar wind. The energy required for whole process comes from thermal energy of the particles.
Michael J. Dunn (11:59:08) :
Finally, it is true that an earthquake can rearrange the elevation contour lines of a given terrain. But it is untrue that the contour lines can rearrange the terrain to cause an earthquake.
Your analogy is false, because a magnetic field has energy [contour lines do not] which can be larger than the energy density of the medium in which case the magnetic field controls the movements of the medium.
Leif Svalgaard (11:08:46) :
“In a dilute, electrically neutral plasma such an imbalance cannot exist for long because the electromagnetic force is so strong: the charges will immediately discharge [the battery goes flat]. To maintain a current you need to continuously separate the charges [against their mutual extremely strong attraction].”
This , above, discussion completely ignores the physically observed & measured double layers in space plasma (and in the laboratory) that accelerate electrons and ions in opposite directions (plasma has a self-organizing ability — that’s why Langmuir named it plasma) thus generating charge seperation. Plasma infused with electric currents generates the magnetic fields which are ubiquitous in space (yes, magnetic fields induce charged particle motion and influence direction of movement, but as a secondary effect).
But astrophysicists continue with this dogma about magnetic fields being the primogenitor to electric currents in space because many if not most of their postulates about the Universe ignore electric current and electric fields in space.
Should this fallacious dogma (like so-called “magnetic reconnection”) get exposed as error, then a large chunk of astronomy would be exposed as gibberish.
(And their control over funding would be severly weakened, opening new avenues of investigation, observation & measurement, by others with counter-ideas, that would potentially expose astronomy’s numerous fallacies even more, and, thus, loosen their grip on power and money even more — always follow the money.)
Michael J. Dunn (11:59:08) :
I have studied magnetohydrodynamics, plasma physics, and astrophysics in my graduate education, which regrettably was too long ago for me to raise a banner and charge into the fray.
Nevertheless, I can side with those who point out the fundamental unreality of magnetic field “lines.” Such lines are only an intellectual construct; the reality is the continuous magnetic field, which is a vector field. A useful metaphor would be the elevation contour lines on a topographic map. The underlying reality is the terrain. There are no “connecting” or “crossing” contours.
Yes, I agree. They are unreal limits of a system (the magnetic field in this case) created in the researcher’s mind for facilitating their study. It is the same with Higgs’ fields; our Universe is permeated by the continuum we recognize like Higgs’ fields. Nevertheless, we have parceled it into small quadrants which in any particular case would serve as boundaries of the studied system, mind-constructed, however.
Yes, I agree. They are unreal limits of a system (the magnetic field in this case) created in the researcher’s mind for facilitating their study. It is the same with Higgs’ fields; our Universe is permeated by the continuum we recognize like Higgs’ fields. Nevertheless, we have parceled it into small quadrants which in any particular case would serve as boundaries of the studied system, mind-constructed, however.
The “bangs”, which occur where the magnetic field is fluctuating, take place thanks to quantum tunneling. QT is evident given that the magnetic field transverses just in those places where the magnetic field density is reestablished.
Fabron (12:42:02) :
James F. Evans (12:43:44) :
Nasif Nahle (13:02:46) :
Folks, I’ll leave you happy in your pseudo-science. Have fun.
Fabron (12:42:02) : Subrahmanyan Chandrasekhar ‘s “time of relaxation” among stars is analog with brownonian movements in a gel.
“”” Zeke (15:52:20) :
Geo. E Smith
I know! I don’t like the language any more than you do! But there it is,
“Magnetic lines of force cross, cancel, reconnect and—Bang! Magnetic energy is unleashed [at some location?] in the form of heat and charged-particle kinetic energy.”
&
“But how? How does the simple act of crisscrossing magnetic field lines trigger such a ferocious explosion?”
Although, isn’t that an argument for the Big Bang? If the Universe is
expanding, it may be worked back to a point, or location, where the explosion occured. So we are occasionally asked to believe in points. “””
Well Zeke, I am afraid that you are missing the fundamental idea. Points, lines (straight), circles, spheres, ellipses, etc, are all constructs of a completely fictitious mental invention of human beings. They are defined by the properties they exhibit in the completely fictional mental exercise that we call mathematics. And we have many varieties of mathematics which we use as tools as needed to explain the behavior of equally fictional “models” of our view of the universe; they do not explain the universe itself. Some of our mathematics seems intuitive; some of it is far from intuitive.
Everybody is familiar with Euclidean geometry that seems to describe our ordinary three dimensional space that is around us; but other geometries create ideas that are totally foreign to our everyday experience.
For example, in Euclidean geometry, we all know that a circle (x^2 + y^2 = r^2) is a borderline case of an ellipse; nand we can put cirles anywhere and describe numerous properties of them; such as Euclid’s nine-point circle theorem for example.
But in “projective geometry”; which is based on different axioms from Euclidean geometry, a circle is not an ellipse at all, it is a special case of a hyperbola. Therefore all circles are infinite sized in projective geometry; and every possible circle intersects every other possible circle; and moreover they all do so at exactly the same two unique points which are called the “Circular Points at Infinity”.
Nothing in our experience behaves like that; and nothing in nature exhibits those bizarre properties; but that isn’t a problem, because nothing in nature is idential to anything in Euclidean geometry either. These are merely tools which we engineered to our liking, and endowed them with defined properties, so that we can use them to explain exactly how our equally fictitious models of reality work. We try to construct our models and their accompanying mathematics to enable us to manipulate the models and determine their behavior. Hopefully, we can get our models to behave similarly to the way we think we observe the real universe to behave.
When the comparison fails; we revise the rules of the models, and thereby change the behavior of the models in order to more closely emulate real life observations. That is what theoretical science is all about; the real universe is far too complex to explain in any readily intelligible way; but we can make models that emulate the universe, which we can explain.
So a point can exist in our mathematics; but none can be found in the real universe; and a magnetic field “line of force” can only have a single direction at any point on that line of force (in our model of magnetism), and hence intersection is disallowed, since it requires two different directions for the force acting at that pint of crossing.
It’s not a question of language; it is that the language has very specific meanings in science; and that often is distinct from the lay usage of the exact same word in a non scientific application.
Those funny “reconnections” are not other than LIGHTNINGS or cross-circuits which we have seen to occur not only in storms but in atomic explosions,before and after earthquakes, etc., and their intensity depends on power (electromotive force).
It is fine to use lines to visualize things. But how can a magnetic field “line” (a representation for a direction and current) open? Then it wouldn’t be a magnetic field anything anymore. Magnetic field “lines” always flow back into the magnet and around. So you either have an open snapped line, OR a magnetic field, but you can’t say it’s both. And if it doesn’t open, then it can’t reconnect.
That is how I see it.
And it may be that astrophysicists are not as familiar with what engineers know as they should be. Perhaps on this issue of reconnection, the fragmentation and extreme specialization of the sciences is more glaring than usual:
Abstract—A majority of baryons in the cosmos are in the plasma
state. However, fundamental disagreements about the properties
and behavior of electromagnetic fields in these plasmas exist
between the science of modern astronomy/astrophysics and the
experimentally verified laws of electrical engineering and plasma
physics. Many helioastronomers claim that magnetic fields can
be open ended. Astrophysicists have claimed that galactic magnetic
fields begin and end on molecular clouds. Most electrical
engineers, physicists, and pioneers in the electromagnetic field
theory disagree, i.e., magnetic fields have no beginning or end.
Many astrophysicists still claim that magnetic fields are “frozen
into” electric plasma. The “magnetic merging” (reconnection)
mechanism is also falsified by both theoretical and experimental
investigations.
Index Terms—Magnetic fields, Maxwell equations, merging,
plasmas.
Dr. Don Scott
http://members.cox.net/dascott3/IEEE-TransPlasmaSci-Scott-Aug2007.pdf
A very readable and amply illustrated paper published by the IEEE
Bookmarked for review.
By way of explanation, the reason why a layperson like me might be so interested in the subject of magnetic reconnection is that it turns out to be a process of major importance in astrophysics. It is invoked to explain many phenomenon–and though I might bring to the discussion many knowledge gaps, I still find it fascinating and well worth an attempt to get to the heart of the issue.
A humble, partial list of the effects of magnetic reconnection:
1. it creates trillions of watts of power which is directed back toward the Earth’s upper atmosphere
2. in solar flares,
it can heat gas to temps of 20 million K
is the source of intense x-ray and gamma ray radiation
it can accelerate particles to almost the speed of light
3.”Magnetic reconnection is intrinsically involved in the dynamo”
4.”Many theories of coronal heating propose that coronal plasma is heated by a superposition of small localized reconnection events”–again, it is explaining why the temp of the corona is millions of degrees hotter than the “surface” or photosphere of the sun.
My thought is that other explanations might exist for these incredibly energetic observed effects. The power and the speed seems to be lacking in magnetic fields lines “crisscrossing” in plasma.
[I have quoted from P.K. Browning’s “Magnetic Reconnection and Dynamos in Laboratory Plasmas”
http://books.google.com/books?id=dTlHvBUoHzcC&printsec=frontcover&source=gbs_navlinks_s#v=onepage&q=&f=false ] pg 73
Also interesting is Attila Grandpierre’s Abstract, just following, on pg 83.