Magnetic Mayhem

[peter09]

Has anyone heard about this before, I cannot quite understand how this is reconciled with current cosmological thinking.

http://www.physorg.com/news/2011-06-voyager-magnetic-mayhem.html

[Dotini]

Yes, this is closely related to NASA's IBEX missions, which is also making delightfully puzzling discoveries at the heliosheath.

http://science.nasa.gov/science-news/sc ... jan_ibex2/

http://www.nasa.gov/mission_pages/ibex/ ... ndary.html<-- Must See weird video

Respectfully submitted,
Dotini

[77Jack]

I could be wrong but that sounds an awful lot like Voyager is going through a double layer.

[Marnee]

I could be wrong but that sounds an awful lot like Voyager is going through a double layer.

Interesting. Could you really quickly explain why you say that so I can understand better, please? Thanks ahead of time.

[nick c]

"The expectations of NASA scientists are not being met because their shock front model is incorrect. The boundary that Voyager has reached is more complex and structured than a mechanical impact. It conforms more closely to the effects seen in electric discharges in gases at low pressures, discovered by Irving Langmuir in the 1920's and 30's. Until the fabulous journey of the Voyager spacecrafts scientists have not been so confronted with the electrical nature of the Sun and its galactic environment."
—Wal Thornhill, 29 September 2006.

>>A simple diagram of the characteristics of a glow discharge (after Cobine). Here the Sun is the anode at the right and the discharge into the interstellar plasma is similar to that of a high-voltage transmission line in air—commonly referred to as a "corona discharge."

It is a plasma sheath, or "double layer" of charge that separates the solar plasma from the interstellar plasma. The double layer forms part of the larger electric circuit of the solar Z-pinch. The double layer carries current and has an inner region of negative charge density and an outer region of positive charge density. Between the charge layers is a strong electric field. Allowing for the vast hourglass shape of the Sun's galactic circuitry, which will distort the pattern found by the Voyager spacecraft from the expected spherical shape, there are some general observations that can be made about what to expect. The complexity of plasma behavior makes it impossible to be highly specific.

The first significant feature encountered by Voyager as it moves from right to left in the diagram is the reversal of the electric field, which decelerates solar wind protons and accelerates electrons along the magnetic field lines. This effect gave NASA scientists the impression that Voyager had reached a hypothetical termination shock. It explains why the deceleration of the solar wind protons was greater than expected ("sluggish solar wind') and no ACR [anomalous cosmic ray] particles were found being accelerated there. Also beams of electrons were often found streaming out from the Sun along the magnetic field lines.

The electric field is strongest near the virtual cathode and it accelerates galactic electrons toward the Sun, leaving a region of positive space charge. The energetic electrons will ionize neutral interstellar particles that are drifting through the plasma sheath. It seems likely that those formed to the right of the voltage peak will experience acceleration toward the Sun to become anomalous cosmic rays. The voltage maximum in the diagram may, as Langmuir noted, be higher than the Sun's potential by an amount sufficient to account for the maximum energy of anomalous cosmic rays.

However, the most interesting effect may be found in the "cathode drop" region to the left of the voltage peak, where the powerful electric field has been estimated to accelerate solar wind protons away from the Sun at cosmic ray energies of the order of 10 billion electron volts. It seems that all stars generate cosmic rays in this way with energies that reflect the driving voltage of the star. The effect on a charged Voyager spacecraft could be very interesting too.

Wal Thornhill

Voyager Probes the Sun's Electrical Environment

[tayga]

FTA

While passing through the heliosheath, Voyager 1 experienced many sudden and drastic changes in the surrounding magnetic field driven by structures called current sheets.

What? There's electricity in space?

[77Jack]

I could be wrong but that sounds an awful lot like Voyager is going through a double layer.

Interesting. Could you really quickly explain why you say that so I can understand better, please? Thanks ahead of time.

They're just talking about going through changing magnetic fields and charged particles changing direction. I honestly said that more out of a gut feeling than any kind of technical knowledge.

I should probably just keep my big mouth shut till I learn more

[mharratsc]

You can hardly go wrong with saying 'double-layer' and 'star (or Sun)' in the same sentence, Jack.

This is exactly what we're looking at here. You have the solar charge gradient on one side of the heliosheath, and the galaxy's on the other side of it.

Like Mr. Thornhill said about Voyager crossing that boundary: "The effect on a charged Voyager spacecraft could be very interesting too."

That could very well be one of the great understatements of the New Millenium... o.O

[hertz]

when voyager hits the galactic "mains" will it be pulled toward the center, thrown out, or disintegrated?

[mharratsc]

Well ya know- I don't think anyone is really willing to stick their necks out on this one. :\

Consider the following:

- we've never actually seen anything ever cross a boundary such as this. Heck, no one is as of yet absolutely certain what the boundary even is.

- even if the EU hypothesis is correct regarding charge differentials, what can we expect to see with such a tiny little thing crossing over into such a mindbogglingly large area of charge? What will be the density of charge carriers on that side? Will equalization be instantaneous, or will the sparse density of carriers allow Voyager to maintain it's own 'sheath' for some time?

- regardless of what happens, will we even be able to determine the results? If Voyager survives the crossing, will we still be able to even hear her RF broadcasts after she passes beyond that monster-sized plasmasheath? Is it tenuous enough that we would still be able to receive broadcasts, perhaps?

All these things are unknowns, as far as I know. It's enough to keep you on the edge of your seat though, that's for sure!

[hertz]

should definitely be interesting...nasa is holding a press conference thursday, 9 june, at 1pm EDT to discuss the latest findings, namely "a turbulent sea of magnetic bubbles" at the edge of the solar system...doubt you'll hear any new enthusiasm for EU, but we'll see...could be that voyager 2 might pick something up before V1 gets "tumbled"

[jjohnson]

Mike said

what can we expect to see with such a tiny little thing crossing over into such a mindbogglingly large area of charge?

Here's a thought experiment. Let's make two assumptions: Voyager has a charge differential relative to the double layer or heliosheath, and outside the heliosheath will be a large interstellar Birkeland current flow (BC).

The charged up Voyager has a certain mass, a certain net surface-charge buildup, and is moving into and across the heliosheath double layer and into the magnetic field of the BC. It's very tiny out there in the cosmic scale of these things, very much like an electron 1.) being emitted by an electric field from an emitter plate in a vacuum tube and then 2.) entering a magnetic field.

1.) As a charged particle enters an electric field in a certain direction, the field will exert a force in the direction of the field upon the particle. Which way depends on the charge of the particle: the convention is that a field designates which way a positively charged tiny "test particle', like a proton, would be accelerated by the field. If Voyager is positively charged, then it would have a force exerted upon it as if it were a proton. If negatively charged, it would have the force applied in the opposite direction. This constantly applied force is maintained in the same direction on the Voyager through its duration in the double layer. If it is crossing the electric field at an oblique angle it will be partially accelerated or decelerated along its path of flight, and the component of the electric field at right angles to the trajectory will tend to curve the path - the velocity vector changes in both speed and direction.

2.) Assuming that Voyager manages to leave the double layer with some velocity into the BC and its magnetic field, we have the second part of the scenario. (Notice that I have ignored any magnetic field interactions in the double layer portion, because I have no idea how strong those might be. They could be significant.) Now we have a particle entering a magnetic field. The magnetic field is likely more or less aligned with the BC current flow direction. The Voyager is entering "cross-wise" to some degree, with a velocity component that may be partly aligned with the magnetic field and a second component at right angles to that, across the magnetic field. Whatever velocity vector Voyager has in the parallel direction to the current and magnetic field, it will be accelerated or decelerated along that "drift" direction by the BC's own electric field. In the long run this tends to align charges with the magnetic field, and can, over long times and distances result in very fast, field aligned particle trajectories (currents). However, a particle entering a magnetic field with a finite velocity will be accelerated or "bent" by a centripetal force that is perpendicular to both the magnetic field and the particles velocity vector, into a cyclotron or Larmor orbit, with a rotational frequency that is proportional to the mass being accelerated, its entering velocity, its amount and polarity of net charge, and the magnetic field strength. Lightweight single charges like an electron travel in very tight, fast trajectories, and more massive or less charged particles or bodies move in wider, slow Larmor orbits. What they "orbit" are "lines" (imaginary of course) of constant magnetic field strength. A particle trajectory, if it enters exactly at right angles to a magnetic field, has no net drift and will simply circle in place. If it enters obliquely it will have a net drift impressed on the circular orbit and a helical trajectory results. The presence of an electric field can also cause a net drift and a helical trajectory. (Fundamentals of Plasma Physics, Bellan, 2006, Cambridge University Press.)

So, if the double layer and the BC electric and magnetic fields behave upon the Voyager as if it were an electron passing through an electric field and into a magnetic field, that might be approximately what happens. In real life, things are seldom as simple as theory and "laws" make them out to be, especially in cosmic plasma, but at least it's a possible first cut at what might be expected. If the polarity of Voyager's charge applies a decelerating force upon her, she might be reflected back into the heliosphere. Her trajectory out into the interstellar medium may be in quite a different direction than that before this transition through the heliosheath or heliopause, and there may be a long term helical component observable, possibly by Doppler shifting of radio transmissions (if any).

Would anyone like to comment on why comets are not reported to follow helical trajectories, if they are charged bodies as EU thinking alleges and they are crossing through the interplanetary magnetic field generated by the Sun?

Jim

[webolife]

Jim,
Do you mean "helical trajectories" other than the obvious ones they trace as a result of following the sun around the galactic disk? This may be a matter of basic relativity to Earth-bound observer n'est-ce pas?

[Dotini]

Would anyone like to comment on why comets are not reported to follow helical trajectories, if they are charged bodies as EU thinking alleges and they are crossing through the interplanetary magnetic field generated by the Sun?

Here's an interesting paper which mentions 3 meteors, thought to be fragments from comet 73P Schwassmann–Wachmann 3, with twisting tails.
http://rspa.royalsocietypublishing.org/ ... 7.abstract

Respectfully,
Dotini

[jjohnson]

@webolife; yes; I meant their specific trajectory, wherein a charged particle or body undergoes Larmor rotation about a central "guiding axis" due to the centripetal acceleration imposed by a magnetic field.

@Dotini; I see the mention of the twisting tails, but no picture and no text to explain if the meteors themselves exhibited any corkscrew motion during their observed flight, or only the tails, or the particles in the tails.

What I was getting at is scale — that a massive body, possibly with relatively low charge for its size, may have such a slow cyclotron period (time per complete revolution) and such a wide Larmor radius that such an orbital perturbation might well go unnoticed or be attributed to something other than magnetic field acceleration, unlike tiny low-mass charges typically considered in plasma physics and electrodynamics.

Jim