The sun's magnetism was detected as soon as astronomers started to analyse the effect it had on the spectrum. Magnetism doubled spectrum lines making a spectrum line for an element appear to be double. The same element viewed through a spectroscope in a laboratory produces only one spectrum line in the same place. This discovery of magnetism on the sun's apparent surface has given rise to some of the most fanciful ideas about how it is produced and what its properties are. The problem is that magnetism around the sun is very easily detected while its cause has generally been ignored. In addition, magnetism on or near the sun's apparent surface has had properties ascribed to it that can't be detected when magnetism is studied on Earth.
Relatively recent research into deep sky objects like distant galaxies indicates that the laws of physics are apparently the same throughout the detectable universe. In particular it has been noted that distant stars and galaxies have spectra that match the spectra we can observe on Earth. From that it is reasonably assumed that other physical phenomena comply with the same laws of physics as the observed spectra. From this it can be deduced that the properties of magnetism in the vicinity of the sun are the same as on Earth. The properties of magnetism on Earth are easily defined.
Magnetism on Earth
Magnetism is exclusively a property of an electric current. Magnetism produced by an electric current can induce permanent magnetism in some ferrous materials. There is no way that magnetism can be produced by any agency other than an electric current.
A magnetic field is invisible. Its influence can be seen by using fine particles of ferrous material and by its effect on currents in ionised gases.
A magnetic field will always take the shortest possible path. The effective magnetic field length is shorter through some ferrous materials. It is this property that enables a magnet to attract ferrous objects.
Magnetic fields take two forms. Typically they are circular or cylindrical around a current carrying straight wire or bipolar as with a solenoid or a permanent magnet.
Magnetic fields are generally static while the electric currents that produce them are in continuous motion. The magnetic field around a wire carrying a steady current is unchanging. If a wire is surrounded by an unchanging magnetic field no current is generated. Please note that the relationship between an electric current and magnetism is a one way phenomenon. Only an electric current can produce magnetism.
If a conductor is in a changing magnetic field or if a conductor is moved within a magnetic field, a current is induced in the conductor. The magnetic field of the induced current will be opposite the magnetic field that induced the current. (This is described in Lenz's Law.)
A magnetic field always declines in strength smoothly as the distance from its source increases. There are no sudden step changes in the strength of a magnetic field associated with distance from its source.
Magnetic fields of opposite polarities are attracted to each other. Magnetic fields of the same polarity repel each other.
Two wires that are close to each other carrying currents in the same direction are attracted to each other because their magnetic fields combine to form one magnetic field. Two similar wires carrying currents in opposite directions are repelled from each other. The electrons in a television cathode ray tube are effectively current carriers travelling in the same direction. Their magnetic fields combine to form an overall magnetic field that makes the electrons move closer together to form the thin beam needed for a television display.
There is no energy in a magnetic field but a magnetic field can act as a means of transmitting mechanical energy. Energy is consumed when a magnetic field is created. The energy used in creating a magnetic field is released when the magnetic field collapses. It is this principle that makes a car's ignition coil work.
Some ferrous materials act as concentrators for magnetic fields. Special iron alloys are used in the transformers used to alter the voltages of alternating currents. The transformers used for electricity supplies have an efficiency that sometimes exceeds 95%.
Finally, some misconceptions about magnetic fields must be laid to rest. Magnetic fields cannot become "entangled" as some sources claim. A magnetic field is not a fluid, it is a form of stress in spacetime. When two or more magnetic fields interact they form a resultant field. The evidence for this is in the way that the deflection system in a television cathode ray tube operates. Two sets of magnetic fields are set up at 90 degrees to each other to control the position where a spot will appear on the screen. One changes at high speed at around 15,000Hz and the other operates at 50 or 60 Hz. The result is a consistent display of lines on the screen.
Another misconception is that there is such an entity called magnetic energy. There is no energy in magnetism itself. Energy is expended when magnetism is created. This energy is released when electric current that created the magnetism ceases. Once a magnetic field has been created it behaves in much the same way as the magnetic fields of bar and horse shoe magnets. Horseshoe and bar magnets consume no energy and provide no energy. A magnetic field can be used as a means of transmitting mechanical energy. Then it acts in a manner analogous to a lever.
A magnetic field can never appear spontaneously. Many sources ascribe astronomical phenomena to the effect of magnetic fields without making any reference to the energy sources that caused the electric currents that produced the magnetic fields.
As with solar phenomena, the principal energy source in the universe is heat. Heat can ionise atoms and cause them to move. Gravity can work in conjunction with heat to cause convection and affects the way ionised atoms move. Moving ionised atoms form an an electric current that produces a magnetic field around itself. The magnetic field thus produced will cause the the atoms in the current to form a thin stream.
The Sun's Magnetism
Now that most of the properties of magnetism on Earth have been covered, the question is, how do these properties tie in with what is observed in the vicinity of the sun?
The problem that sun observers have is that whereas the magnetism is fairly easily detectable, its causes are not. This is because the magnetism is caused by movements of ionised gas that is mostly invisible. There is one form of the invisible ionised gas that can be detected near the Earth. It is the solar wind. The solar wind is so transparent in the visible and infra red spectra that it does not appear to be there, even when viewed through 93 millions of miles of it in the same direction as the sun. The solar wind is emitted from the sun in all directions When stars are viewed that are apparently adjacent to the sun during a total eclipse, the solar wind does nothing to alter their appearance. We know that the solar wind comes from the sun and consists of highly ionised particles. That means that there must be a lot of invisble particles in the sun's atmosphere. Moving ionised particles are an electric current. Every electric current has a magnetic field around itself.
From this we can conclude that all magnetic fields in the vicinity of the sun are created by moving ionised gases, most of which are invisible. The temperature below the apparent surface of the sun is high enough to ionise the gases that make up the sun. The apparent surface of the sun is a sort of boundary that is generally accepted as being the photosphere. The photosphere has a temperature of 5800K. It is the part of the sun that is cooled by radiation while reducing or even stopping light and heat from being emitted from the layers below it.
Magnetism has only one type of source. In a comparable way, light has only one fundamental source. Light (and heat) are distributed by photons. Photons are liberated from atoms when electrons descend from a higher energy level to a lower one. When an atom liberates a photon it becomes less ionised. In the sun the degree of ionisation of an atom is more or less related to its temperature. Atoms emerging from the depths of the sun below the photosphere become cool enough to emit the photons that form the photosphere.
We usually detect the presence of matter by the electromagnetic radiation it emits. It may be infra red or visible light or some other radiation like radio waves or x-rays. All of these forms of radiation are produced by the emission of photons. The matter itself may be the original emitter of photons or a reflector of the photons that collide with it. When an atom has become as ionised as is possible, it has no electrons available that can fall from a higher energy level to a lower one. Atoms in this state are generally referred to as ionised particles. Observations of comparable ionised particles in the vicinity of the Earth are restricted to to the strength of their electric charges and by the effect they have when they collide with un-ionised atoms. These particles emit no photons and reflect no photons. They are invisible in (apparently) all electromagnetic parts of the spectrum. These invisible particles are all emitted from the sun. It is therefore logical to assume that there are dense clouds of these invisible particles in the vicinity of the sun.
The sun generates its heat by converting matter into energy. We know of the basic properties of heat. One definition of heat is the degree of thermal agitation of atoms. Atoms that have higher thermal agitation take up more space. In other words they expand as they become hotter. A consequence of a body of atoms getting hotter and expanding is that it becomes less dense than its surroundings. This gives rise to convection when the body is free to move. When the movement of the heated body is restricted, its pressure rises in proportion to the temperature it reaches.. An analogous situation occurs in a saucepan of boiling rice on Earth when most of the water has boiled away. Steam is generated at the bottom of the saucepan that escapes by bursting through the overlying layers of cooler rice. It leaves holes in the rice at its surface. Evidence for something similar happening below the sun's apparent surface is indirect but there are countless instances of it all over the the apparent surface shown in NASA images of the sun. The gas emitted from below the sun's apparent surface is hotter than the surrounding photosphere. However, as it is released it expands and cools somewhat. As the temperature is related to the degree of ionisation, the cooling gas is becoming less ionised. In this state it is able to emit some photons. The ejected gas has mass and the sun has gravity that is 28 times as strong as the Earth's. The ejected gas falls back to the apparent surface of the sun in an arc. It is still ionised although less so than it was before it was ejected. As it is a moving ionised gas it has magnetic field around it. Its magnetic field affects it in the same way as the magnetic field around a stream of electrons causes the the electrons to form a thin beam in a cathode ray tube. The ejected gas is confined to a thin stream as it forms an arc as it ascends and descends. It will be noted in the NASA images that there is a burst of brightness around the origins of these arcs of ionised gas. I presume that this is caused by the sudden cooling that occurs as the gas bursts through the sun's apparent surface. This cooling allows more atoms to emit photons in the region where the gas is ejected.
The next part is conjecture based on observations of NASA images. The arcs of gas observed over the sun's apparent surface appear to occur in pairs in many instances. The material ejected returns to the sun's apparent surface at nearly the same speed as when it was launched. This will cause the returning material to bore its way down below the sun's apparent surface. This will create a local hot spot below the sun's apparent surface. It is conceivable that the heated material in this hot spot will give rise to a further ejection of hot ionised gas. The easiest way for this gas to escape is via the hole made by the gas that bored its way down to the place where the hot spot was generated. As a result a jet of gas is ejected back along the path of the original jet. However.this returning jet has a magnetic field around it that is repulsive to the magnetic field of the original jet. Thus the two jets are kept apart from each other while following nearly identical paths. The returning second jet's material and energy could help to reinforce the source of the original jet, enablimg it to be sustained. Moving NASA images seem to indicate that the pairs of jet arcs are maintained for periods of a minute or more. The mutual support that pairs of jet arcs give each other could be the reason for their apparent longevity.
These jet arcs are small in comparison to other ejections of material from below the sun's apparent surface. The causes of these larger ejections are almost certainly similar to the smaller jet arcs that have been observed. The largest of thes ejections that fall back toward the sun's apparent surface are known as prominences. It is my belief that the launch points and crash points of these prominences create the holes in the sun's apparent surface that are known as sunspots. These holes appear darker than the photosphere because the atoms in them are too hot and ionised to emit many photons. It is known that the atoms in prominences appear to be very dim in comparison to the photosphere. I think that they are dim because they are too hot to emit many photons.
The next stage is also conjecture.
I have explained a mechanism whereby two small jet arcs can apparently support each other for a while. I think that the origins of prominences are much deeper within the sun than the origins of the jet arcs that are easily seen in the NASA images. The material in a prominence that crashes back to the sun's apparent surface must bore down to a comparable depth to the energy source that launched the prominence. It may well behave in a comparable manner to the way pairs of jet arcs seem to maintain each other. However, the returning material from a prominence will arrive at one side of the energy source that produced the prominence. This could well help to maintain the prominence while pulling its source in the direction of the place where it crashes back to the sun's apparent surface. This fits with what is observed about sunspots. Sunspots move around the apparent surface of the sun in pairs and are also relatively long-lived.
If a prominence is just a giant version of the jet arcs seen in the NASA images, an enormous amount of material will be ejected at an extremely high speed from its source. As the material ejected will be highly ionised, the jet of material will have a colossal magnetic field around the place it comes from. This is in close agreement with the strong magnetic fields detected around sunspots.
In the foregoing explanations of some of the
observable sun's phenomena I have only referred to the one source
of energy that the sun has in super abundance - heat. The heat
generated within the sun causes what would be called vulcanism
on Earth. No magnetism has ever been created on Earth by heat
alone. It is therefore reasonable to presume that the sun's heat
does not create magnetism either. The material ejected by the
sun's vulcanism is made up of highly ionised atoms. These atoms
are predominately hydrogen and helium atoms. At a temperature
of around 10,000K almost all hydrogen is ionised. Helium is almost
completely ionised at around 15,000K Temperatures at these levels
are common just below the sun's apparent (photosphere) surface.
At greater depths the temperature is considerably higher. The
circumstatial evidence indicates to me that atoms heated to 15,000K
or higher do not emit many photons. The evidence for this is indirect
but nevertheless easily accessed. For example, the solar corona
emits so little light that it only becomes visible during a total
eclipse. Its temperature is higher than 15,000K. Some sources
offer very high temperature estimates. The low light emission
at these very high temperatures supports my hypothesis that some
regions give off less light than the surrounding photosphere because
they are very much hotter. Further support comes from the solar
wind itself. It is totally invisble yet consists of highly ionised
particles. It gives out no light and does not reflect light. Temperatures
are generally estimated by the spectrum of radiation emitted.
The mean temperature of the solar wind is indeterminate. The solar
wind comes from the sun which is undoubtedly extremely hot. Its
strength increases when there are more sunspots visible. This
means that sunspots are sources of some of the solar wind. As
the solar wind is invisible, whatever is emitted from sunspots
is also invisible. As the solar wind consists of ionised particles
that have been launched from the sun at a speed greater than the
sun's speed of escape, sunspots must be launch sites for some
of the solar wind. I hypothesise that one of a pair of sunspots
is a launch site for what is known as a prominence. Some of the
material launched in a prominence will exceed the sun's speed
of escape, adding to the strength of the solar wind.
Other emissions from the sun in the form of solar flares and coronal mass ejections cause temporary increases in the strength of the solar wind. Like the rest of the "normal" solar wind, these emissions are just as invisible. Corononal mass ejections and solar flares can be observed as occuring at the sun's apparent surface when they occur. There is a lot of information available soon after the material is launched about when it is likely to hit the Earth and what its effects could be. There is almost no information about the material launched that does not achieve the sun's speed of escape. It must return to the sun's apparent surface. As the material is largely invisible like the solar wind itself, what happens to the returning material is apparently not observed.
The foregoing observations about the Sun's
magnetism are based on empirical evidence about the properties
of magnetism on Earth and the assumption that magnetism on the
Sun has the same properties. It has the same cause - an electric
Nobody has ever detected magnetic lines of force on Earth. They are a result of a misinterpretation of what is seen when iron filings are scattered over a piece of paper laid over a bar magnet. Each iron filing in the magnetic field becomes an induced magnet with its own north and south poles. In line with the axis of the magnetic field iron filings are attracted to each other forming chains that are effectively very long thin induced magnets. Adjacent chains of filings are long induced magnets are of the same polarity and are therefore mutually repulsive. The separation of these adjacent chains of induced magnets gives the appearance of lines between the north and south poles of the bar magnet. The positions of these chains of induced magnets are decided by chance. If the iron filings on paper over a bar magnet experiment is repeated it will be found that no two patterns of lines of induced magnets is the same. There are no lines of force that will cause lines of induced magnets to form in the same places when the experiment is repeated. There are therefore no magnetic lines of force. Any explanations based on the existence of magnetic lines of force or just magnetic lines have as much validity as the magnetic lines of force that do not exist. If it is accepted that magnetic lines of force do not exist, The explanations about sunspots in Wikipedia by Horace Babcock are ludicrous if not laughable.
Wilf James BSc. 05/04/2012