The following introduction to some technical terms should
provide a reasonable insight into Plasma Physics. An underlying simplicity seems
to beckon, even while many questions remain, and a picture drastically different
from the traditional view of the universe begins to emerge.
The Solar Wind
The Earth's magnetic field acts much like a protective
cocoon. Over and around this field flows the solar wind, the dilute but persistent
stream of plasma (protons, electrons and other ions) emitted by The Sun. This
flow of plasma, with its associated electromagnetic fields, distorts The Earth's
own field, compressing it on the dayside and stretching it on the night side.
The resulting field is called the magnetosphere.
Because the sun is seen
to emit roughly equal quantities of ions and electrons, the solar wind is considered
electrically neutral in mainstream circles. This is wrong. In reality it is a
huge bipolar electric current, and the terms solar wind and solar radiation result
from the fact that the mainstream refuses to acknowledge electricity in space.
Moreover, plasmas react with the extensive magnetic field lines in our solar system,
and when conducting fluids flow through a magnetic field a dynamo can be created,
with the electrical energy needed to drive the current taken from any relative
motion. This is consistent with the laws of physics: If a closed circuit exists,
parts of which are moving through a magnetic field while other parts are not,
an electric current will arise. This is how dynamos work.
Magnetospheres
Magnetic forces are of little importance in our everyday
lives and require a sensitive instrument like a compass needle to be detected.
This is because most of the materials we encounter, from the ground we walk on
to the air we breathe, are electrically neutral.
At 60
miles or more above the surface of the Earth, however, the situation is very different.
The fringes of the atmosphere at these heights are dominated by plasmas which
react with the earths magnetic field, steering and trapping the energised particles.
The intense activity in these regions is sometimes described
as one of the first surprises of the space age, and the sheer scale of the magnetospheres
of other planets has also taken many by surprise, consistent though they are with
Plasma models.
Magnetotails
In contrast to the dayside of the magnetosphere, which
is compressed and confined by the solar wind, the night side is stretched into
a long tear-shaped 'magnetotail'. This part of the magnetosphere is quite dynamic,
where the ions and electrons are often energized (the magnetotail is the main
source of the polar aurora).
The plasma sheath of Venus is extremely
long, almost touching the Earth when the two planets are at their closest approach.
NASA astronomers recently discovered 'stringy things' in the tail, as predicted
by Birkeland.
Birkeland currents
Magnetic disturbances are usually observed during displays in auroral zones.
These are localised and fade towards the equator, suggesting that currents flow
nearby. Currents, of course, require closed circuits. Birkeland proposed that
these currents flowed from space at one end of an auroral arc and returned to
space at the other, flowing parallel to the ground when in proximity with The
Earth.
Birkeland first made this proposal after returning from an expedition
to an auroral zone in 1903, and it was confirmed by the US Naval satellite, Triad,
in 1973. Its magnetometer detected two large sheets of electric current, down
on the morning side of the auroral zone, and up on the evening side, as expected.
Each sheet typically carries a million amperes or more.
Enormous Birkeland currents connecting Jupiter and its moon Io were recorded by
the Voyager spacecraft in 1979.
In
1984 Farhad Yusef-Azdeh, Don Chance, and Mark Morris discovered Birkeland currents
on a galactic scale. Working with the Very Large Array radio telescope, they found
an arc of radio emission some 120 light-years long near the centre of the Milky
Way! The structure is made up of narrow filaments typically 3 light-years wide
and running the full length of the arc. The strength of the associated magnetic
field is 100 times greater than previously thought possible on such a large scale,
but the field is nearly identical in geometry and strength to computer simulations
of galaxy formation.
Current
modes
Electric currents in plasma take on three basic modes
— dark, glow or arc — depending on the voltage and charge density. In laboratory
gas-discharge tubes, voltage and charge density vary non-linearly between the
electrodes and produce segments that are alternately dark and glowing. The high-charge-density
arc mode is used in industry for precision machining.
The
plasma sheath of venus, mentioned above, is currently in dark mode.
Z-pinches
The
plasma universe consists of swirling streams of electrons and ions flowing in
filaments which tend to corkscrew or spiral. They self pinch from the magnetic
fields that they generate around themselves.
There is a tendency for these filaments to repel at close range, and attract at
greater distances. However, when in close proximity they may also spiral around
one another. When this happens there is also a tendency
for the filaments to compress between them any material (ionized or not) in the
plasma. This is called the Z-pinch effect.
The bulk
of the filaments are invisible from a distance, much like the Birkeland currents
that circle the Earth are invisible from its surface, with the exception of auroral
discharges.
Doubleness
The proclivity for multiple filaments to interact in pairs is
a signature of electromagnetic forces and sometimes referred to as 'Doubleness'.
This behaviour derives from Ampére's Law or the Biot-Savart force law
which states that currents in the same direction attract while currents in the
opposite direction repel. They do so inversely in relation to the distance between
them. This results in a far larger ranging force of interaction than the gravitational
force between two masses. Gravitational force is only attractive and varies inversely
with the square of the distance.
Electromagnetic force strength
While all matter is subject to gravity,
plasma is more strongly affected by EM forces as is to be expected given its constituent
parts — negatively charged electrons and positively charged ions. In fact, the
EM force is 10^39 times as strong! Plasma displays structures and motions that
are far more complex than those found in neutral solids, liquids, and gases. It
has a tendency to form the cellular and filamentary structures under discussion.
The
following is quoted from from Dr A. Peratt's site
"...But
perhaps the most important characteristic of electromagnetism is that it obeys
the longest-range force law in the universe.
"When
two or more non-plasma bodies interact gravitationally, their force law varies
inversely as the square of the distance between them; 1/4 the pull if they are
2 arbitrary measurement units apart, 1/9 the pull for a distance of 3 units apart,
1/16 the pull for 4 units apart, and so on.
"When
plasmas, say streams of charged particles, interact electromagnetically, their
force law varies inversely as the distance between them, 1/2 the pull if they
are 2 arbitrary measurement units apart, 1/3 the pull for a distance of 3 units
apart, 1/4 the pull for 4 units apart, and so on. So at 4 arbitrary distance units
apart, the electromagnetic force is 4 times greater than that of gravitation,
relatively speaking, and at 100 units, apart, the electromagnetic force is 100
times that of gravitation.
"Moreover,
the electromagnetic force can be repulsive if the streams in interaction are flowing
in opposite directions. Thus immense plasma streams measured in megaparsecs, carrying
galaxies and stars, can appear to be falling towards nothing when they are actually
repelling..."
"The underlying assumptions of cosmologists today are developed with the most sophisticated mathematical methods and it is only the plasma itself which does not 'understand' how beautiful the theories are and absolutely refuses to obey them." Hannes Alfvén
Double Layers
Plasma sheathes were discovered by Langmuir in his laboratory,
and are now called double layers.
DLs refer to one of the most important properties
of any electrical plasma — its ability to form electrically isolated sections
or cells. Because Plasma is an outstanding conductor and cannot sustain a high
electric field, it self-organizes to form a protective sheath (Double Layer) across
which most of the electric field is concentrated and where most of the electrical
energy is stored (They can act very much like capacitors).
When a foreign
object is inserted into a plasma, a DL will form around it, shielding it from
the main plasma. This effect makes it difficult to insert voltage sensing probes
into a plasma in order to measure any electric potential at a specific location.
Double layers may break down with an explosive release of electrical energy.
Hannes Alfvén first suggested that billions of volts could exist across
a typical solar flare DL.
Astrophysicists who map magnetic fields and assume
there's no electricity in space (or little of any consequence) seem, somewhat
inexplicably, to be unaware of their existence. They resort to positing any number
of mechanical devices from 'magnetic reconnection' to 'frozen-in magnetic field
lines' and more.
"In
the beginning was the Plasma." Hannes Alfvén
'Frozen-in Magnetic Fields'
The myth of 'frozen-in magnetic fields' still raises its
head in the mainstream now and again, despite Alfvén disposing of it many years
ago. For years it was assumed that plasmas were perfect conductors and, as such,
a magnetic field in any plasma would have to be 'frozen' inside it.
The basic
technical reason for this arose from one of Maxwell's equations. It was thought
that if all plasmas are ideal conductors they cannot have electric fields (voltage
differences, inside them), and that any magnetic fields inside a plasma must therefore
be 'frozen', that is unable to move or change in any way.
Thanks to Alfvén we now know that there can be voltage differences between different
points in plasmas. He pointed this out in his acceptance speech when receiving
the Nobel Prize for physics in 1970. The electrical conductivity of any material,
including plasma, is determined by two factors: the density of the population
of available charge carriers (the ions) in the material, and the mobility of these
carriers. In any plasma, the mobility of the ions is extremely high. Electrons
and ions can move around very freely in space. But the concentration of ions available
to carry charge may not be at all high if the plasma is very low pressure or diffuse.
In short, although plasmas are excellent conductors, they are not perfect. It
therefore follows that weak electric fields can exist inside them, and magnetic
fields are NOT frozen inside them.
"Never attribute to malice that which can be adequately
explained by stupidity, but don't rule out malice."
Heinlein's Razor
'Magnetic reconnection'
Like the myth of 'Frozen in magnetic fields', Magnetic
Reconnection is another colourful invention of conventional astronomy. It also
attempts to account for anomalies arising from the misconception that electric
currents do not flow in space.
In reality it is a well-understood plasma phenomena,
relating to exploding double-layers and electric discharge. Astronomers have noticed
that when magnetic reconnection occurs, there seem to be regions of electron-depleted
space associated with it (Electric Currents). They have also noticed that a two-layer
flow of particles is created that speeds the release of energy (Double Layers).
Don Scott, a retired professor of electrical
engineering, explains the issues in more detail here
'Magnetars'
Magnetars are mathematical-models of stars based on
'frozen-in' magnetic fields and 'magnetic reconnection'. Need we say anymore?
The math may be correct, but this does not guarantee that they reflect reality.
Plasma cosmologists know that magnetic fields do not stand alone — they
are induced by electric currents. There must be an intense electric current feeding
the magnetar, and this current must be part of a circuit, as all electric circuits
must be closed.
"Magnetic
Reconnection is pseudo-science." Hannes Alfvén
Power generation
Because plasmas are good, but not perfect, conductors,
they are similar to wires in their ability to carry electrical current. It is
well known that if any conductor cuts through a magnetic field, a current will
flow in that conductor. This is how electrical generators and alternators work.
If
there is any relative motion between a cosmic plasma, say in the arm of a galaxy,
and a magnetic field in that same location, currents will flow in the plasma.
These currents will, in turn, produce their own magnetic fields.
In 1986,
Hannes Alfvén postulated electrical models on both galactic and solar scales.
Physicist Wal Thornhill has pointed out that Alfvén 's circuits are really scaled
up versions of the familiar homopolar motor that serve as the watt-hour meters
in many homes. Also, more recently, the interaction of the Moon Io with the giant
planet Jupiter has been likened to a dynamo.
There is still some discussion
as to whether galaxies require electrical power from external sources, but who
can now reasonably deny that vast currents flow throughout space? For how much
longer can this simple fact be overlooked and denied?
Granted, electric
currents in space may be more difficult to measure than magnetic fields, but the
'truth is out there'.
"In
order to understand the phenomena in a certain plasma region, it is necessary
to map not only the magnetic but also the electric field and the electric currents."
Hannes Alfvén
Scaling Plasmas
Plasma phenomena are scalable. Their electrical and physical
properties remain the same, independent of the size of the plasma. In a laboratory
plasma, of course, things happen much more quickly than on, say, galaxy scales,
but the phenomena are identical — they obey the same laws of physics.
In other
words we can make accurate models of cosmic scale plasma behaviour in the lab,
and generate effects that mimic those observed in space. It has been demonstrated
that plasma phenomena can be scaled to fourteen orders of magnitude. (Alfvén hypothesised
that they can be scaled to 28 orders or more!)
Electric currents flowing
in plasmas produce most of the observed astronomical phenomena that remain inexplicable
if we assume gravity and magnetism to be the only forces at work.
Plasma simulations
A world renowned electrical engineer, Dr Anthony C. Perratt
— a graduate student of Nobel Prize winner Hannes Alfvén — has worked on plasma
simulations for many years. See the links page for further details of this leading
light in Plasma Physics.
He has utilized super-computing capabilities to apply
the Maxwell-Lorentz equations (the basic laws governing the forces and interactions
of electric and magnetic fields) to huge ensembles of charged particles. He calls
this PIC - Particle In Cell simulation. The results are almost indistinguishable
from images of actual galaxies.
Peratt Instabilities
One of the latest and most important discoveries. These
dynamic effects are observed to occur in intense Birkeland currents, arc discharges
in plasma torches, z-pinched plasma filaments, and high energy electrical discharges.
The instability takes on the shape of a column of axially symmetric toroids or
spheroids that remain in a semi-stable state until disruption. These instabilities
can also take on a sawtooth structure with a violent snaking motion.
Magnetohydrodynamics
The study of the dynamics of electrically-conducting fluids,
one of many fields pioneered by Alfvén, and perhaps one of his better known contributions
within mainstream circles.