In the first part, I gave a brief overview of the Plasma Universe. And I mentioned that Peratt
was interested in looking at galactic scale filaments and their interaction.
He saw that a long-range attractive force would cause the filaments to pull towards each other
and this most often occurred in two to three filaments.
In this part, we will explore this concept in more detail and understand how they could explain
double radio galaxies and quasars in a totally different way. Let’s dive in and find out more.
Double Radio Sources
The existence of double radio galaxies has presented a major challenge to cosmological
theories. The discovery of these objects dates back to the pioneering survey
conducted by Reber. He found that two bright radio sources in Cygnus and Cassiopeia.
Cygnus A is the brightest radio source in the constellation Cygnus.
Most models of radio galaxies are based on the characteristic of this source.
There are many theories and models of what radio galaxies are and regardless of whatever
ingredients are postulated as necessary in models used to explain their existence,
what is observed from any radio source is synchrotron radiation,
which requires only the presence of relativistic electrons in a magnetic field.
Any plausible theory on double radio galaxies should be expected to explain the following:
The origin and source energy of double radio galaxies
The total magnitude of the radio flux observed
The measured flux density as a function of frequency
The observed shape and in particular the radiation hotspots and their displacement
off an imaginary axis running from one giant radio lobe through an elliptical centre with the lobes
The one-sidedness of jets in quasars and powerful sources
The apparent faster than light motion of some sources
The problem of nearly uniform fading of some jets The polarisation properties
of the measured radiation The lifetime and evolution of a source.
Peratt used the following parameters for his simulations
When the long-range attraction between adjacent pinched Birkeland filaments pulls them closer
than a few filament radii the short-range repulsion each feels will cause a redistribution
of the synchrotron emitting relativistic electron currents within the filaments. The result of this
is an increased current density in the form of rings in the outer edges of the filaments leading
to an edge brightening. This dance with the attractive and repulsive forces will also cause
the filaments to twist around each other which in turn causes a displacement of the current density.
This will also cause a tendency to further filamentation as the current tubes are
flattened into sheet beams. The cross-sectional regions of dense synchrotron emitting electrons
are called hotspots and are analogous to their double radio galaxy counterparts.
During the time that the electromotive force driving the Birkeland currents exists,
both axial current and associated azimuthal magnetic fields increase.
This will produce a change in the distribution of magnetic field energy as shown here.
As the sequence continues we find that the initially strong source continues to rotate
around the central axis and weakens significantly.
The initial shape of strong classical double radio galaxies
are largely determined by the magnetic energy density
of the interacting Birkeland filaments. Later on, double radio galaxies project more complex
patterns which are the result of the induction acceleration of plasma confined between isobars.
As the axial currents and resultant azimuthal magnetic fields around each filament increases,
the magnetic field will become concentrated
and if we represented this strength in isobars it would look like this. The effect of the colliding
magnetic fields is to produce an isobaric sump with an elliptical cross-section.
These converging magnetic field lines will compress intergalactic
plasma into two narrow channels formed on either side of the elliptical sump.
At this stage, a channel exists on the right-hand side in this simulation.
The condensation of plasma from the cosmic plasma medium involves two mechanisms.
The pinching of the plasma within the current conducting filaments
The capture and compression of plasma between the filaments
Within a filament, the convection velocity of plasma radially inward
is three times faster than the force of attraction between the filaments. The approximate velocity of
isobaric compression in the region of the sump is 9 times faster than this.
From this, we can see that the incoming plasma closely resembles the closing of two giant cymbals
as is often the case for peculiar galaxies located between giant radio lobes that possess
dust lanes in their midsection. Over time this convection velocity decreases over time whereas
the compression velocity increases until a pressure equilibrium is reached in the sump.
It is important to point out that Peratt did not simulate the behaviour of the plasma in this sump
due to the demands of the spatial resolution in the simulation. Lerner has studied this state
in some detail and points out the similarity to pinch regions in the dense plasma focus.
This is a point I will be coming back to in a future video.
The phenomena associated with the capture and compression of intergalactic plasma
between neighbouring Birkeland currents in synchrotron emission
can best be seen from the observational evidence itself. Here we can see double sources for which
no central object of any kind is present. While these show sources in which large
redshift objects have formed at or near the geometric centre between filaments.
Here again, we see the formation of double sources where the central object is identified as galactic
in nature and usually has a large redshift, and is generally of elliptical or peculiar in morphology.
What is noticeable is the development of a one-sidedness in Synchrotron radiation.
As can be seen, an isobaric channel starts to form on the right-hand side of the sump, or core.
The channel continues to form and narrow. Then the converging magnetic field line morphologies ceases
to support a channel on the right-hand side but rapidly forms a new channel on the left-hand side.
The plasma electrons confined in these channels are responsible for the synchrotron radiation
observed. It is important to understand that the synchrotron radiation from the channel plasma is
only possible when the polarity of the induction field in the channel is correctly aligned.
This would mean that in order for an outward observer to view the synchrotron radiation
there would have to be an electric field directed into the screen.
So at time T=255 we see that the field component in the left-hand channel is directed out of the
screen, while the strong field component in the more well defined right-hand channel is
directed into the screen. This source projects a channel or ‘jet-like’ radiation pattern out of the
screen that is connected to a strong core. This is also the direction in which the synchrotron
radiation from the electron Birkeland currents making up the outer radio lobes is beamed.
The rapid spatial variation of the induction field,
as well as the changing of the field polarity along the channel, causes an apparent faster
than light or superluminosity effect as the field sweeps the channel confined plasma.
These superluminosities are often associated with radio sources.
During his simulations, he was able to measure apparent superluminosities of seven times the
speed of light. This electromagnetic wave effect for illumination as a source of superluminosity
was first suggested by Kellerman back in 1980 in his paper “Radio galaxies and quasars”.
The left-hand side of the beam in this case is tethered to the denser core,
but the right-hand side is free to fold. This configuration matches what we see from sources
like M87 and 3C273. The bends in the sheet beams, either extragalactic or laboratory,
delineate where the dynamics of the beam change from that of a linear rigid rotor to a nonlinear
vortexing beam. Typically this change occurs when the beam has rotated some 10-30deg
about the major axis. It is important to realise that the sheet beam is produced between the
converging isobars and is inductively accelerated our of or into the screen.
So are these really jets coming out? The term jet was first used in astrophysics by Curtis
in 1918 to describe the elongated optical feature protruding from the core of the elliptical galaxy
M87. Later Baade and Minkowski suggested that such a jet might correspond to matter ejection after
some active phase of the core. Jets are found not only in double radio galaxies and quasars
but also in central compact radio sources located in the nucleus of associated optical galaxies.
They are measured from the synchrotron radiation they emit this ranges
from a few electromagnetic wavelengths ranging from centimetres to X-ray.
However, in spite of improved resolution and statistics of observations, definitive
direct evidence that ordered streaming motions are present in jets or radio sources is still missing.
Moreover, uncertainty exists in identifying structures as either jets or bridges.
The induction field across the channel is variable, causing the confined plasma to
brighten and fade. When we examine how the M87 jets have evolved over time we can clearly see
that the jet itself has not moved but instead, the brightness has changed and in general, has faded.
Peratt was able to access records dating back to 1952 and was able to measure the total jet
intensity had fallen by at least 2.5 magnitudes while no overall change in shape was observed.
This indicates that the fading is happening across the entire channel more or less uniformly.
There are however some images that appear to show the motion of at least part of the jet
but it is possible that this is simply parts being lit up as the induction field sweeps through it.
For now, I want to leave the discussion on this and the overall concept until the final part
as this will show how the continued twisting of the Birkeland currents
can explain how a galaxy would evolve over time into a spiral galaxy.