Sun and Earth Electrically Connected By "Magnetic Portals"
It seems that solar and heliospheric astronomers / physicists are making great leaps and bounds in their understanding of our dynamic relationship with our local star (the Sun). Recent new observations by Cluster and THEMIS have given new insight into the mutual electrical interactions. But do astronomers and physicists 'get it?'
In a previous story, it was noted that Cluster had detected what scientists called density holes (or "bubbles," for lack of a better term) where the magnetosphere meets the interplanetary plasma. It was found that they were of considerably lower density but also considerably higher temperature than the surrounding plasma.
The bubbles, known as density holes, are regions of space where the density of gas suddenly falls by ten times but the temperature of the remaining gas leaps from 100,000ºC to 10,000,000ºC.
The energy source to drive these bubbles is currently uncertain but there is strong circumstantial evidence that the collision of the solar wind with the Earth’s magnetic field, which forms a boundary known as the bow shock, is probably creating the energy to drive them.
While astronomers and heliospheric physicists seem to be in shock about such "unexpected" data, an alternate interpretation based upon plasma physics seems to be quite comfortable with the results:
In the half-century following Explorer 1, almost all the great surprises of space age exploration of the solar system have involved electromagnetic activity. We now know that the Earth is surrounded by a complex structure of magnetic fields and high-speed charged particles that include streams of electric current around the Earth. This structure has been named the "magnetosphere" under the assumption that it forms the boundary between the Earth's and the Sun's magnetic fields.
However, comets form similar protective sheaths, visible as their comas, without having magnetic fields. In a plasma discharge most objects naturally form a Langmuir plasma sheath that prevents direct contact with the enveloping plasma. Magnetospheres are merely a more complex form of Langmuir sheath, with the magnetic field of the body trapped within the sheath. If standard theory failed to anticipate these discoveries, surely the primary reason lies in the failure to recognize that planets are embedded in a solar electric discharge and consequently enveloped by Langmuir sheaths.
For these reasons, the original contributions of Kristian Birkeland should no longer be ignored.
Evidence continues to mount that the space surrounding Earth is rife with electrical activity. Where mainstream astronomers see “superhot gases” that “pop” and “fizz,” proponents of the Electric Universe see plasma double layers doing what they are observed to do in plasma experiments.
Since the 1960’s, space probes have revealed that Earth’s auroras are caused by electrical currents flowing from the Sun – a fulfillment of the prediction of plasma pioneer [Kristian] Birkeland. The Earth’s magnetospheric “bubble” is actually a Langmuir sheath that is electrically coupled to currents flowing in the Sun's heliospheric sheath. Sheaths are composed of electrically charged double layers of plasma, in which layers of opposite charge build up very near each other with a strong electric field between them. These double layers accelerate ions to high velocities that, when interpreted as temperature, appear to be very “hot.”
Two regions of dissimilar plasma will form a Langmuir sheath between them, which may result in a “bubble” formation. Electrical theorists such as Wallace Thornhill suggest that the so-called “fizzy bubbles” are most likely sheath-bounded cells of plasma. They are more than a magnetic effect in gas: they will exhibit charge differential, ion acceleration and radiation over a wide band from radio to x-ray—all suggesting a much different line of investigation than that implied by the story of “fizzy bubbles” in space.
Another recent news release confirmed the long-standing assertion made by Birkeland that the Sun and Earth were involved in an electrical exchange.
The original press release, of course, did not explicitly mention the electrical nature of the events nor the pioneering work of Birkeland that predicted such a discovery a hundred years ago. Only in an associated multimedia image was the electrical nature of the event properly characterized as a 650,000 Amp current flowing into the Artic.
The latest results from Cluster and THEMIS are a bit more complicated in scope and interpretation. However, to summarize, they have observed what they characterize as "magnetic portals" with a cylindrical character, through which charged particles (traceable all the way back to the sun's atmosphere along "magnetic field lines") flow across the magnetospheric boundary. These "portals" appear to open and close regularly in short bursts approximately every 8 minutes. The mission scientists are not sure why these bursts occur nor why they are short bursts rather than a continuous flow.
"It's called a flux transfer event or 'FTE,'" says space physicist David Sibeck of the Goddard Space Flight Center. "Ten years ago I was pretty sure they didn't exist, but now the evidence is incontrovertible." ... The European Space Agency's fleet of four Cluster spacecraft and NASA's five THEMIS probes have flown through and surrounded these cylinders, measuring their dimensions and sensing the particles that shoot through. "They're real," says Sibeck.
What exactly is 'fluxing' or being transferred, you might ask? Read on.
Researchers have long known that the Earth and sun must be connected. Earth's magnetosphere (the magnetic bubble that surrounds our planet) is filled with particles from the sun that arrive via the solar wind and penetrate the planet's magnetic defenses. They enter by following magnetic field lines that can be traced from terra firma all the way back to the sun's atmosphere.
"We used to think the connection was permanent and that solar wind could trickle into the near-Earth environment anytime the wind was active," says Sibeck. "We were wrong. The connections are not steady at all. They are often brief, bursty and very dynamic."
It seems that the flux in question is an electrical flux, a flow of charged particles from the sun to the boundary of our planet's plasma sheath and then tricking through it. Currents, such as these, flowing along magnetic field lines are generally known as 'field-aligned currents' or as 'Birkeland currents,' named after the Norwegian scientist (Kristian Birkeland) who predicted, way back in the early 1900's (circa 1908), just such currents flowing between the Sun and Earth along magnetic field lines. Not only did Birkeland predict such currents, he demonstrated empirically in the lab how such currents would work.
The press release continues:
Approximately every eight minutes, the two fields [of the Earth and Sun] briefly merge or "reconnect," forming a portal through which particles can flow. The portal takes the form of a magnetic cylinder about as wide as Earth.
...the cylindrical portals tend to form above Earth's equator and then roll over Earth's winter pole. In December, FTEs roll over the north pole; in July they roll over the south pole.
Sibeck believes this is happening twice as often as previously thought. "I think there are two varieties of FTEs: active and passive." Active FTEs are magnetic cylinders that allow particles to flow through rather easily; they are important conduits of energy for Earth's magnetosphere. Passive FTEs are magnetic cylinders that offer more resistance; their internal structure does not admit such an easy flow of particles and fields. (For experts: Active FTEs form at equatorial latitudes when the IMF tips south; passive FTEs form at higher latitudes when the IMF tips north.) Sibeck has calculated the properties of passive FTEs and he is encouraging his colleagues to hunt for signs of them in data from THEMIS and Cluster. "Passive FTEs may not be very important, but until we know more about them we can't be sure."
There are many unanswered questions: Why do the portals form every 8 minutes? How do magnetic fields inside the cylinder twist and coil? "We're doing some heavy thinking about this at the Workshop," says Sibeck.
One is tempted to point out that there is a direct relationship between magnetic fields and electric currents.
Electric current produces a magnetic field. The magnetic field can be visualized as a pattern of circular field lines surrounding the wire.
Electric current can be directly measured with a galvanometer, but this method involves breaking the circuit, which is sometimes inconvenient. Current can also be measured without breaking the circuit by detecting the magnetic field associated with the current.
It seems that the description offered by Sibeck can be understood rather simply in electrical terms. Assuming their simple description holds. A long, straight electric current will produce a cylindrical magnetic field around it. In fact, short of a permanent magnet, an electric current is about the only way to produce a magnetic field!
In answer to the question above "How do magnetic fields inside the cylinder twist and coil?", it might be said "they don't."
'Magnetic field lines' are only a visualization tool on paper or in simulation. They are not real entities any more than lines of longitude, lines denoting elevations on maps or lines denoting the edges of pressure systems on weather maps. Field lines only give an estimate of the strength and direction of the magnetic field at a given instant in time. If the geometric configuration of an electric curernt changes, the 'magnetic topology' (the overall appearance of magnetic field lines in 2 or 3 dimensions) immediately changes to indicate the new field vectors and strengths. There can be neither tangling, knotting, coiling nor cutting of objects that are only a visualization tool, not reified objects.
The simple answer is that when we see magnetic topologies change, it means there was a change to the underlying system of current(s).
It seems that what is being observed is an electrical discharge across a section of the magnetosphere (the Earth's Langmuir / plasma sheath).
It is then interesting to note that the aforementioned scientists working under assumptions factoring in known laboratory plasma physics have also offered a possible explanation:
Earth: A Self-repairing Capacitor
One electrical device which serves as a model for cosmic plasma activity is the capacitor. A capacitor is a device for accumulating and storing electric charge. It is made of two conductors separated by an insulating medium. When charge is placed on one conductor it attracts charge of the opposite polarity on the other conductor. As a result, an electric field is set up between the conductors, a reservoir of electrical energy.
As the charge on the capacitor increases, the electric field between the conductors will increase, placing a growing stress on the insulator. At some critical point, the insulator breaks down and the capacitor "short circuits," releasing the stored electrical energy suddenly. Such breakdowns may destroy a solid insulator and with it, the capacitor.
However, if the charging rate is slow and the insulator is air or liquid, the damage may repair itself as fresh insulating material rushes in. That is a "self-repairing" capacitor. If the current is strong or the insulator weak, current will pass between the conducting plates, either steadily or in bursts. This is called a "leaky capacitor."
Many natural systems form capacitors as well. For example, the Earth's surface and its ionosphere are two conducting layers separated by air. The surface-ionosphere capacitor is of particular interest in the study of sprites. Small "leaks" in the form of lightning can trigger much larger "leaks" (sprites, etc.) at high altitudes above them.
In this light, perhaps the "magnetic portals" can find a simple explanation in electrodynamics, via the description above of a leaky capacitor. Charges from the solar wind accumulate on one side of the plasma sheath (an insulating plasma "double layer") increasing the electric field across the insulator until a "dielectric breakdown" occurs and a brief electrical discharge occurs across the plasma sheath.
An electric current would have the natural effect of producing a magnetic field radial to the current direction. If the current is more-or-less straight, the magnetic field will be more-or-less cylindrical.
The 'leaky capacitor' idea may provide an explanation as to how and why the 'magnetic portals' open and close cyclically ('leaky capacitors' can, as noted above, suffer from bursts of discharges, much like the cyclicality of 'magnetic portal' production). In other words, charge builds up, a dielectric breakdown occurs, a discharge occurs, the discharge quenches and the dielectric (insulating plasma) rushes back in to resume insulation. If charges build up cyclically, it seems to follow that dielectric breakdowns would occur in similar cyclical pattern.
If astronomers and heliophysicists are willing to hear an alternate explanation, leaving aside "magnetic reconnection," which the father of plasma physics and Nobel prize winner Hannes Alfvén always considered to be pseudoscience, an answer might be in the offing.