__Part One:__The Basics of Electrodynamics & How It Relates to PEMF DevicesIntroduction The Electromagnetism- Forces, Energy, & Waves

I. Electrostatics - Charges at Rest (Electric Charge, Coulombs Law & Gauss's Law)

II. Charges in Motion Part 1 (Voltage, Capacitance & Basic Circuits)

III - Introduction to Magnetism, Magnetic Forces and Magnetic Fields

**IV. Magnetism Part 2 - Lorenz Force Law, Biot Savart Law, Ampere's Law & The Really Big Lie in PEMF!!!**

V. Faraday's Law of Induction & Applications to PEMF Therapy

__Part Two:__The Physics of Energy TransferVI. - Electric Power and Transformers- Electric Energy Transfer and Inductive Energy Transfer.

VIII. Maxwell's Equations - Bringing it ALL Together

IX. Solving Maxwell's Equation for Free Space (Homogeneous Solutions) - LIGHT

X. Solving Maxwell's Equations Most General Solution (Inhomogeneous solutions) - Velocity and Acceleration fields (bound and free fields). Now we can talk about the different types of energy medicine devices and make CLEAR distinctions.

XI. Resonance - Mechanical, Electromagnetic and Wireless Power Transmission

XII. Magnetic Resonance Stimulation - The Choral Fantasy

Let us Start with Electricity and Electric Charge:

**IV. Magnetism Part 2 - Lorenz Force Law, Biot Savart Law, Ampere's Law & The Really Big Lie in PEMF!!!**

**From Magnetism to Electromagnetism**

For thousands of years, the only known sources of magnetic fields were certain iron ores and other materials that had been accidentally or deliberately magnetized.

That all changed in October 1820, when Hans Christian Oersted accidentally discovered that an electric current produces a magnetic field. He noticed that a compass needle was deflected near a wire and moved when an electric current was passed through the wire. This suggested that the current in the wire was producing a magnetic field that affected the compass.

Shortly after this discovery French physicist Andre Marie Ampere heard about Oersted's discovery and within ONE WEEK Ampere had begun quantifying the relationship between electric currents and magnetic fields called Ampere's law (more on this later).

So Within a short period Electricity and Magnetism became forever connected at last in one Field of Study - Electromagnetism!

**What Oersted Found...**

Whereas stationary charges produce an electric field, moving charges in addition produce a magnetic field. In fact magnetic fields are easier to detect, all you need is a boy scout compass. Now if you hold a tiny compass in the vicinity of a current carrying wire, you quickly discover a peculiar thing:

The field does not point toward the wire nor away from it, but rather it circles around the wire. In fact if you grab the wire with your right hand - thumb in the direction of current - your fingers curl around in the direction of the magnetic field (

**Right Hand Rule**).

Andre Marie Ampere was experimenting with some wires trying to learn more about the connection between currents and the magnetic fields they create.

**Here is what Ampere Found...**

He took two parallel wires and ran a current through them in the same direction and the wires attracted each other. When he ran a current through both wires in the opposite direction, the wires repelled each other.

Because both wires are electrically neutral (which is obvious when the current is turned off), it is not electrostatics (so Coulombs law does not apply). Also noteworthy is that if you place a stationary charge next to a moving current, nothing happens.

__Magnetism is caused by moving charges and FELT by moving charges!__

The Lorenz force law equation quantifies the magnetic force.

**2 Right Hand Rules...**

When a charged particle moves through a magnetic field B, it feels a

**Lorentz force**F given by the cross product:

F = q (v x B)

q is the electric charge of the particle, and

v is the velocity vector of the particle

In the Presence of both electric and magnetic fields the total force is F = Q[E + v x B]. Cross products are usually used in physics with rotation or circulation, in this case it is because the magnetic field circulates around the wire.

Use the 2nd right hand rule to determine the direction of the force.

Note: Typically electric forces are enormously greater than magnetic ones. Has to due with the fundamental constants eo and uo.

The reason the magnetic force can dominate in a current of wire is that the overall charge of the wire is electrically NEUTRAL... that is, in metals electrons can move free around BUT the protons and positive charges exactly balance it out.

We looked at magnetic field strength in the last video, here we can see how the Tesla arises from the force law.

A 1 tesla magnetic field exerts a force of 1 N on a charge of 1 Coulomb moving at 1 m/s.

A 1 tesla magnetic field exerts a force of 1 N on a charge of 1 Coulomb moving at 1 m/s.

**Magnetic Forces in Action - The Earth's Magnetic Field and the Magnetic Force...**

The sun is constantly shooting radiation towards us in the form of charged particles. Luckily for us, the earth has a magnetic field for protection.

The Lorenz force law says that Magnetic fields exert a force on single electric charges that pass through it. This is exactly what the earth's magnetic field does to the charged particles coming from the sun... It defects them and sends them spiraling away protecting us from the worst of the radiation.

Charges perpendicular to the magnetic field lines experience the strongest forces, like the earth.

These Same Magnetic Forces are Moving Charged Ions in PEMF devices helping the cells to recharge cellular voltage

So we have been talking about magnetic forces arising from steady currents and acting on moving charges or other currents, let's now look at how the magnetic field is generated by current in a wire.

A

We explored in the last video basic ideas of Magnets, Magnetic Fields, Magnetic forces, magnetic North and South Poles, and Magnetic field strength based on the qualitative and visual idea of flux lines.

Remember we saw visually that the greater the density of flux lines (like illustrated in iron filings around a bar magnet), the stronger the magnetic field.

A

**magnetic field**is a field produced by a moving charge or current that is used to exert a magnetic force on another moving charge or current. For simplicity we will always assume the current is flowing steadily through a very thin wire.We explored in the last video basic ideas of Magnets, Magnetic Fields, Magnetic forces, magnetic North and South Poles, and Magnetic field strength based on the qualitative and visual idea of flux lines.

Remember we saw visually that the greater the density of flux lines (like illustrated in iron filings around a bar magnet), the stronger the magnetic field.

**First we have the Biot Savart Law - Equation for Calculating Constant Magnetic Fields around steady currents.**

Like the Equation for the Electric field from Coulombs law, the Biot Savart Law is the analogous Formula to Calculate the Magnetic Field around a steady current.

The Biot Savart Law Basically says that every little segment of wire dL with current I, will produce a a little magnetic field dB. (dL and dB stand for infinitesimally small wire segments and magnetic fields respectively).

It is one nasty formula, because unlike Coulombs law, where the cause of the electric field is a point charge, the CAUSE OF A MAGNETIC FIELD is a tiny line segment of current (and vector), dL. It is only a 1/r^2 law for point charges in motion and small dL segments of current, which never happens in PEMF devices.

Why? Because to get the Total magnetic field we need to Integrate or Add the magnetic field contribution of each little line segment over the entire length of the wire. This gives similar distance relations of lines, sheets, loops and other sources as electric fields did.

And we'll see in detail through this course how many PEMF companies and so called PEMF experts promoting high intensity DO NOT USE THIS EQUATION properly. In fact, it seems they do not use it AT ALL!!!

Why? Because to get the Total magnetic field we need to Integrate or Add the magnetic field contribution of each little line segment over the entire length of the wire. This gives similar distance relations of lines, sheets, loops and other sources as electric fields did.

And we'll see in detail through this course how many PEMF companies and so called PEMF experts promoting high intensity DO NOT USE THIS EQUATION properly. In fact, it seems they do not use it AT ALL!!!

Lets Focus on the Equations of a circular loop of current in a wire.

This is extremely important because this is HOW true PEMF devices create a pulsing magnetic field. In fact current loops (as we'll see) are the ONLY way to create a pure magnetic field from current in a wire.

I will not derive it here, but if we calculate the Magnetic field along the center axis of a current loop, we end up with a 1/^3/2 dropoff, NOT 1/r^2. Remember we saw a ring of charge ALSO created an Electric Field that dropped off by 1/^3/2.

Why not an inverse square? We have to integrate or add up all the little current segments to get the TOTAL field. A loop of current depends on TWO variables, the radius of the loop AND the distance away. Larger Loops create larger magnetic fields (which makes sense because there is MORE current flowing in a larger loop) with greater magnetic fluxes and gradients (more on this later).

This is extremely important because this is HOW true PEMF devices create a pulsing magnetic field. In fact current loops (as we'll see) are the ONLY way to create a pure magnetic field from current in a wire.

I will not derive it here, but if we calculate the Magnetic field along the center axis of a current loop, we end up with a 1/^3/2 dropoff, NOT 1/r^2. Remember we saw a ring of charge ALSO created an Electric Field that dropped off by 1/^3/2.

Why not an inverse square? We have to integrate or add up all the little current segments to get the TOTAL field. A loop of current depends on TWO variables, the radius of the loop AND the distance away. Larger Loops create larger magnetic fields (which makes sense because there is MORE current flowing in a larger loop) with greater magnetic fluxes and gradients (more on this later).

So Magnetic Fields DO NOT DROP OFF as an inverse square because there are NO MAGNETIC POINT SOURCES OR MONOPOLES as we seen. And we never use an infinitesimally small segment of wire or sphere of current (current cannot flow steadily on spheres).

This Lie is being told by a LOT OF HIGH INTENSITY so called experts like Dr Pawluk and Marcus Freudenmann, and high intensity companies like Curatron. Basically ALL THESE PEOPLE SELL HIGH INTENSITY DEVICES!!!

Using the inverse square law to justify high intensity is BAD BAD SCIENCE!!

PEOPLE NEED TO UNDERSTAND THIS BEFORE BEING DUPED INTO BUYING EXPENSIVE AND DANGEROUS HIGH INTENSITY. THIS BIG LIE (WHICH IS A BIG ONE), WAS THE PRIMARY MOTIVATION FOR ME DOING THIS COURSE.

Using the inverse square law to justify high intensity is BAD BAD SCIENCE!!

PEOPLE NEED TO UNDERSTAND THIS BEFORE BEING DUPED INTO BUYING EXPENSIVE AND DANGEROUS HIGH INTENSITY. THIS BIG LIE (WHICH IS A BIG ONE), WAS THE PRIMARY MOTIVATION FOR ME DOING THIS COURSE.

Power Tools for Your Health By Dr Pawluk... Big Mistake pps 10-15.

Like Marcus he uses INVERSE SQUARE... THIS IS THE WRONG EQUATION.

Secondly, he didn't even use the inverse square law properly.

0 inches away from a source is an infinite number.

If you use 1/r^2 and put in 0 you get 1/0^2 = infinity.

So honestly I don't know what equation he used.

Also 1, 2, 3 , 4 and 5 when put into inverse square isn't even right. So the the Numbers for % dropoff don't even make sense if you use inches???

Thirdly, he used inches instead of meters (That is the WRONG UNITS and bad dimensional analysis).

I used the CORRECT equation for an 11 cm radius which is what is used in the iMRS 2000 just to give you an idea just how WRONG this is. At 5 inches away the field is still 62% of field at surface. According to Dr Pawluk's bad physics, it is only .5%. That is Dr Pawluk's numbers are off by over 10,000% and it gets worse as you get further away. 10,000% error is unacceptable.

Now if his numbers were correct, which they are not, then his argument for higher intensity might be at least a little more plausible, but as we'll see in the frequency section, resonance is the key, not intensity.

But a BIG PART OF HIS BOOK IS RECOMMENDING MIDDLE TO HIGHER INTENSITY PEMF BASED ON USING THE WRONG FORMULA!!!

Just BAD BAD science!!

I plan on doing a more comprehensive video on this later.

Like Marcus he uses INVERSE SQUARE... THIS IS THE WRONG EQUATION.

Secondly, he didn't even use the inverse square law properly.

0 inches away from a source is an infinite number.

If you use 1/r^2 and put in 0 you get 1/0^2 = infinity.

So honestly I don't know what equation he used.

Also 1, 2, 3 , 4 and 5 when put into inverse square isn't even right. So the the Numbers for % dropoff don't even make sense if you use inches???

Thirdly, he used inches instead of meters (That is the WRONG UNITS and bad dimensional analysis).

I used the CORRECT equation for an 11 cm radius which is what is used in the iMRS 2000 just to give you an idea just how WRONG this is. At 5 inches away the field is still 62% of field at surface. According to Dr Pawluk's bad physics, it is only .5%. That is Dr Pawluk's numbers are off by over 10,000% and it gets worse as you get further away. 10,000% error is unacceptable.

Now if his numbers were correct, which they are not, then his argument for higher intensity might be at least a little more plausible, but as we'll see in the frequency section, resonance is the key, not intensity.

But a BIG PART OF HIS BOOK IS RECOMMENDING MIDDLE TO HIGHER INTENSITY PEMF BASED ON USING THE WRONG FORMULA!!!

Just BAD BAD science!!

I plan on doing a more comprehensive video on this later.

Whichever it is call B has units of Tesla or Gauss Typically. 1 Tesla = 10,000 Gauss. And we'll just refer to it as the magnetic field strength or intensity.

So the answers obtained from using the Biot Savart law will be in Tesla.

So the answers obtained from using the Biot Savart law will be in Tesla.

We talked about different Magnetic Field Strengths in the last video.

Remember to convert to Gauss, just divide by 10,000.

Remember that Tesla and Gauss BOTH MEASURE THE SAME THING, just like Meters and Yards both measure distance.

Many times in PEMF we use terms like Microtesla abbreviated uT. These prefixes are for all scientific quantities. Milli = 1/1000, etc.

So a microtesla which is abbreviated uT = 1/1,000,000 of a Tesla.

The Earth's magnetic field is roughly 33uT at the equation and 66 uT at the Poles. This is simply easier to write than .000033 - .000066 Tesla. Because a Tesla = 10,000 Gauss, we move the decimal place 4 places to the right.

I usually use the Earth magnetic field strength as reference as this is WHERE you basically want to be with PEMF devices.

33 - 66 micro Tesla (uT)

.33-.66 Gauss (G)

The best PEMF devices have intensities that are under 5 Gauss or 500 Microtesla. I will go over this more in the intensity section of the course and you'll see why more is DEFINITELY not better.

Remember to convert to Gauss, just divide by 10,000.

Remember that Tesla and Gauss BOTH MEASURE THE SAME THING, just like Meters and Yards both measure distance.

Many times in PEMF we use terms like Microtesla abbreviated uT. These prefixes are for all scientific quantities. Milli = 1/1000, etc.

So a microtesla which is abbreviated uT = 1/1,000,000 of a Tesla.

The Earth's magnetic field is roughly 33uT at the equation and 66 uT at the Poles. This is simply easier to write than .000033 - .000066 Tesla. Because a Tesla = 10,000 Gauss, we move the decimal place 4 places to the right.

I usually use the Earth magnetic field strength as reference as this is WHERE you basically want to be with PEMF devices.

33 - 66 micro Tesla (uT)

.33-.66 Gauss (G)

The best PEMF devices have intensities that are under 5 Gauss or 500 Microtesla. I will go over this more in the intensity section of the course and you'll see why more is DEFINITELY not better.

**Ampere's Law**

Ampere's law is to Magnetostatics what Gauss's law was to electrostatics. It gives the same answer as the Biot Savart Law but is usually easier to work with.

If you draw a circle around a steady current of wire, the magnetic field will have a set strength on that circle. Ampere realized that the stronger the current running through the wire, the stronger the magnetic field will circulate around that circle.

Ampère's law relates the integrated or summed up magnetic field around a closed loop to the electric current passing through the loop.

More precisely it says that the total magnetic field around a closed loop (which is called the circulation) is equal to the current running through the loop times uo. uo is the magnetic permeability analogous the electric permittivity (more on this in a bit).

So for a steady line of current and using a circular loop, The line integral around the circle is just the summed up total magnetic field of every point around the circle = B*2*pi*R since B has the same value on each point on the circle.

To find B at point a distance R from the current, just divide by the circumference of the circle which is that distance away.

B*L = uo*Ienc

B*2pi*r = uo*ienc

More precisely it says that the total magnetic field around a closed loop (which is called the circulation) is equal to the current running through the loop times uo. uo is the magnetic permeability analogous the electric permittivity (more on this in a bit).

So for a steady line of current and using a circular loop, The line integral around the circle is just the summed up total magnetic field of every point around the circle = B*2*pi*R since B has the same value on each point on the circle.

To find B at point a distance R from the current, just divide by the circumference of the circle which is that distance away.

B*L = uo*Ienc

B*2pi*r = uo*ienc

If you are not able to follow this don't worry, just at least understand that a steady current produces a circulating magnetic field. We can use the right hand rule to determine the direction of the magnetic field and either the Biot Savart Law or Ampere's law to calculate the magnetic field intensity in Tesla at any point in space around the source current. The geometry and strength of the current determines the magnetic field strengths.

Here are a few examples of equations of magnetic fields around various simple objects.

Here are a few examples of equations of magnetic fields around various simple objects.

Again as I mentioned with Electric fields in video #2, note how the magnetic fields depend on the geometry of the charge/currents distributions. Note geometrical ISOMORPHISM of both electric and magnetic fields (and also gravitational fields and light sources).

1) Point or sphere of charge is a 1/r2 dropoff (no equivalent in magnetostatics or PEMF).

2) Infinite (or long) Line of Charge AND a line of current are both 1/r dropoffs

3) Infinite plane of charge or current never drop off (always the same)

1) Point or sphere of charge is a 1/r2 dropoff (no equivalent in magnetostatics or PEMF).

2) Infinite (or long) Line of Charge AND a line of current are both 1/r dropoffs

3) Infinite plane of charge or current never drop off (always the same)

**4) RING of Charge and a RING of current are in Inverse 3/2 dropoff (NOT A 1/r2!!). We'll explore this later as TRUE PEMF devices use a ring of charge.**

The current loop is so fundamental to magnetism that even at the atomic magnetic fields are produces by little current loops. (flat coil)

5) Infinite Solenoid also important. The magnetic field is uo*n*I inside the solenoid and ZERO outside... (tower of coil).The current loop is so fundamental to magnetism that even at the atomic magnetic fields are produces by little current loops. (flat coil)

5) Infinite Solenoid also important. The magnetic field is uo*n*I inside the solenoid and ZERO outside... (tower of coil).

**The Permeability of Free Space**

**μ**

**o**

The constant of proportionality between magnetic circulation on the left side of the Ampere's Law and the enclosed current on the right side is μo, the permeability of free space. Just as electric permittivity characterizes the response of a dielectric to an applied electric field, the magnetic permeability determines a material's response to an applied magnetic field.

The permeability of a magnetic material is often expressed as the relative permeability which is the factor by which the materials permeability exceeds that of free space.

Diamagnetic Materials have slightly less than 1.0 because the induced field weakly opposes the applied field (gold, silver and copper are all arond .99997). The induced field in paramagnetic materials weakly reinforces the applied field, so these materials have a μr slightly greater than 1. Aluminum has a μr of 1.00002.

So magnetic fields in general do NOT get diminished by materials INCLUDING THE HUMAN BODY which overall is weakly diamagnetic with a permeability constant close to exactly 1. This allows magnetic fields to penetrate deeper and work better than light therapy (penetration depth), electric field therapy (dielectrics) and electric current therapy (resistances/impedances). Remember the body had dielectrics that would reduce electric fields 40-50 times!

So magnetic fields in general do NOT get diminished by materials INCLUDING THE HUMAN BODY which overall is weakly diamagnetic with a permeability constant close to exactly 1. This allows magnetic fields to penetrate deeper and work better than light therapy (penetration depth), electric field therapy (dielectrics) and electric current therapy (resistances/impedances). Remember the body had dielectrics that would reduce electric fields 40-50 times!

Only ferromagnetic materials appreciably change the magnetic permeability, but by INCREASING IT. These values range from several hundred for nickel and cobalt and over 5000 for reasonably pure iron. The reason iron amplifies magnetic fields and can remain magnetic is that is has 4 unpaired electrons that can all line up to the magnetic field (and stay line up).

So ferromagnetic materials AMPLIFY the magnetic field considerably!

As we'll see later, the inductance of a long solenoid is given by the expression

L = μr*NumberTurns^2*Area/length

Adding an iron core means ur is 5000 which increases the inductance by 5000 FOLD.

PEMF Note: Only a couple PEMF devices on the market use a probe or pen applicator with a iron core. The iMRS 2000 probe is one of them (and in my opinion the best)!

So ferromagnetic materials AMPLIFY the magnetic field considerably!

**PEMF Example - Use a Ferromagnetic Core**As we'll see later, the inductance of a long solenoid is given by the expression

L = μr*NumberTurns^2*Area/length

Adding an iron core means ur is 5000 which increases the inductance by 5000 FOLD.

PEMF Note: Only a couple PEMF devices on the market use a probe or pen applicator with a iron core. The iMRS 2000 probe is one of them (and in my opinion the best)!

*****There are trace amounts of magnetite (which is ferromagnetic) in the human body, which studies have shown the body can amplify weak magnetic and electric fields, so perhaps it does play an important role in coupling our body to the earth's magnetic field BY AMPLIFYING weak magnetic fields. Again another reason we DO NOT need high intensity PEMF, the body can AMPLIFY WEAK Signals... More on this later.**

**You Cannot Shield Magnetic Fields (like you can with electric fields).**

We just saw that magnetic fields are never really blocked or diminished because unlike the dielectric constants for materials, the magnetic permeability either barely diminishes the field (slightly less than 1) or in the case of ferromagnetic materials, the field is dramatically increased.

Why? Because are no magnetic charges or magnetic monopoles like we mentioned in the last video.

A bar magnetic is called a dipole because it has two poles (the prefix di- means two). If you cut bar magnet in half, it creates two more magnets.

All magnetic field lines MUST TERMINATE on the opposite pole. Because of this, there is no way to stop them - nature must find a way to return the magnetic field lines back to an opposite pole. Where by contrast you can surround and shield an isolated positive or negatively charged electron or ion.

Even LEAD does not block magnetic fields. Again the benefit of this with regards to magnetic therapy, is that magnetic fields are really the ONLY energetic fields that penetrate the human body with no shielding. This leads to deeper healing!

This all comes from an important fact, that ALL pure magnetic fields come from CURRENT LOOPS or DIPOLES which leads us to the true origin of magnetic fields...

If You ask the average person what is magnetism, you will probably be told about your refrigerator decorations, compass needles or the North Pole - none of which has any obvious connection with moving charges or current carrying wires.

Yet, ALL magnetic phenomenon are due to electric charges in motion, and in fact if you could examine a piece of magnetic material on the atomic scale you would find tiny current loops, electrons spinning on axis and orbiting nucleus.

Think of nuclei and electrons as tiny spinning magnets.

Yet, ALL magnetic phenomenon are due to electric charges in motion, and in fact if you could examine a piece of magnetic material on the atomic scale you would find tiny current loops, electrons spinning on axis and orbiting nucleus.

Think of nuclei and electrons as tiny spinning magnets.

**So Magnetism, at its root, arises from CURRENT LOOPS!**

1) Microscopic current loops, Spin magnetic moments of elementary particles --> Gives rise to magnetic materials.

The magnetic properties of materials are mainly due to the magnetic moments of their atoms' orbiting electrons (little electrons orbiting nucleus (current LOOPS) all aligned in bar magnets!).

2) Macroscopic Current Loops - Electric currents in wires and current loops (dipoles). Earth's current is in essence a gigantic current loop (dynamo theory of earth's magnetic field).

So ALMOST ALL MAGNETIC PHENOMENON ARE DUE TO PERFECTLY CIRCULAR CURRENT LOOPS!! This is VITALLY IMPORTANT TO UNDERSTAND IN RELATION TO PEMF DEVICES BECAUSE AS WE'LL SEE THE QUALITY OF THE MAGNETIC FIELD PRODUCES DEPENDS ON THE QUALITY OF THE CURRENT LOOPS. If there are NO CURRENT LOOPS THERE IS NO PURE MAGNETIC FIELD OR PEMF FIELD!!

**The Reason Why the BEST PEMF Devices Use perfectly circular Current Loops.. Because that is the ONLY way to create a PURE Magnetic or Pulsating Magnetic Field!!**

So in true PEMF devices that use a current carrying circular loops, the MAGNETIC component is the STRONGEST just like static magnetics!! A current loop is almost PURE MAGNETIC FIELD LINES IN THE CENTER OF THE LOOP!!!

NOTE: It is Important to closely space the turns or the field lines bleed out and you loose the PURENESS of the magnetic field through the center of the loops, not to mention the strength -

MANY PEMF DEVICES DO NOT USE TIGHTLY WOUND COILS WHICH IS BAD PHYSICS.

VERY IMPORTANT NOTE: Electromagnets are widely used as components of other electrical devices, such as motors, generators, relays, solenoids, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel.

THEY ALL USE TIGHTLY WOUND LOOPS OF CURRENT - PERFECTLY CIRCULAR!!

Why? because that is the ONLY way to create a pure magnetic field with current in a wire!!

More on this in a later module...

Now suppose I stack a whole lot of loops coaxially, say by wrapping a wire around a cardboard cylinder many times into a spiral (like a solenoid). Given that a single loop produces a dipole (N-S) field, we get a field that looks like the solenoid (which is an electromagnet depicted here. This field ALSO looks exactly like a bar magnet as we pointed out earlier. As far as a compass needle is concerned, the fields are identical.

So how does the permanent magnet work? Is it a different kind of magnetism?

NO, everything is coming from electric currents. In the case of the permanent magnet, the currents are coming from the electrons in the atoms.

Every atom has electrons going around the nucleus, and every moving electron is a current.

Imagine for simplicity nine electrons going around their atoms in the plane of a piece of paper shown here. The region in between the atoms they go in opposite directions. They CANCEL. The ONLY thing that does not cancel is the current along the perimeter or edge. THUS, a single layer of atoms can produce a current at the edge. It will be permanent since atomic currents are.

Now think of a magnetic solid consisting of many layers of such atoms. At the edge of each layer is its current. So a magnetic material can effectively have a sheet of current on its surface, which will produce a magnetic field. In the case of the cylindrical magnet shown here, the currents move EXACTLY like the solenoid or electromagnet with currents circulating around it and by the Right hand rule, the magnetic field is exactly what you would expect from a bar magnet. So even STATIC magnets are produced from CIRCULATING currents!!

NOTE 1: The mathematics that describes this is called Stokes Theorem.

NOTE 2: And as we mention before, permanent magnets additionally require that they have ferromagnetic properties where there are many unpaired outer electrons that do not cancel. Like IRON which has four!! But the point is that all magnetic fields come from circulating charges!!

NOTE: Note 3: permanent magnets can lose their magnetism at high temperatures (called the Curie Temperature).

NO, everything is coming from electric currents. In the case of the permanent magnet, the currents are coming from the electrons in the atoms.

Every atom has electrons going around the nucleus, and every moving electron is a current.

Imagine for simplicity nine electrons going around their atoms in the plane of a piece of paper shown here. The region in between the atoms they go in opposite directions. They CANCEL. The ONLY thing that does not cancel is the current along the perimeter or edge. THUS, a single layer of atoms can produce a current at the edge. It will be permanent since atomic currents are.

Now think of a magnetic solid consisting of many layers of such atoms. At the edge of each layer is its current. So a magnetic material can effectively have a sheet of current on its surface, which will produce a magnetic field. In the case of the cylindrical magnet shown here, the currents move EXACTLY like the solenoid or electromagnet with currents circulating around it and by the Right hand rule, the magnetic field is exactly what you would expect from a bar magnet. So even STATIC magnets are produced from CIRCULATING currents!!

NOTE 1: The mathematics that describes this is called Stokes Theorem.

NOTE 2: And as we mention before, permanent magnets additionally require that they have ferromagnetic properties where there are many unpaired outer electrons that do not cancel. Like IRON which has four!! But the point is that all magnetic fields come from circulating charges!!

NOTE: Note 3: permanent magnets can lose their magnetism at high temperatures (called the Curie Temperature).