# Low Level EMF and Helmholtz coil design

## Main Question or Discussion Point

The problem statement:
I want to produce an LL-EMF of a specific amplitude and frequency in a pair of Helmholtz coils of pre determined radius.

The frequency and amplitude are derived from the following equations from this publication http://www.heartrhythmjournal.com/article/S1547-5271(14)01477-5/pdf

Relevant equations:
I have put the powers of 10 in brackets
Equations derived by Jerry Jacobson, DMD,PhD

1) mc(2) = q(j) v B L
where m =target molecule mass = for vasostatin-1 mol weight of 7KD = 7000 x 1.169 x 10(-24)gm
c =velocity of light =2.99 x 10(10)cm/sec
q(j) = 1 ab-coulomb
v = earth's orbital velocity = 3 x 10(6)cm/sec
L =target linear dimension = 1.73 x 10(2)cm
B =magnetic amplitude in Gauss

2)Based on the aforementioned assumptions and hypotheses, Jacobson then
proposed the desired frequency of the applied electromagnetic field by invoking the
cyclotron resonance equation:
f = qB/2(pi)m
where B =magnetic amplitude in Gauss (derived from above equation)
q =normalized charge of electron = 1.602 x10(-19) ab-coulomb
m =norm. mass of electron = 9.1095 x10(-28)

My work so far:
I have worked them through for a human size of 1.73 meters, and get the results as :
B (amplitude in Gauss) = 2.01 x 10(-8)G
f (frequency in Hertz) = 0.56Hz
I can scan and upload my longhand work if needed.

So then to design the Helmholtz coils. Their size should be suitable to centre the magnetic field on the heart area of a human, giving a radius of 35cm (Radius of coils equals distance of separation).
The magnetic flux density at their midpoint is given by:
B =(4/5)(3/2)UnI/R
here U =4PI x 10(-7) T.m/A (permeability of free space)
n = number of turns in each coil
I =current in amps =2.5amps (see below)
R =radius in meters =3.5 x10(-1)
B =derived as above =2.01 x 10(-8)G

I have a frequency generator that outputs 20V p-p maximum, output impedance is 50Ohms, so current should be 2.5 amps

However, when i try to solve the above equation to get the number of turns for the coils, i get 2.37 x10(-3) turns!
Am i using the correct equations?
Thanks,
John

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BvU
Homework Helper
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Do you really want to targtet one (1) molecule ?

Earth magnetic field is about .5 Gauss, so wouldn't it be a lot easier and cheaper to just slowly pirouette ?

Thanks BvU,
I am blindly following the original paper as they had success suppressing fibrillation in dog's hearts by targeting that particular molecule. Are you suggesting to scan through the frequencies when you say pirouette?

BvU
Homework Helper
2019 Award
No I mean you rotate physically. Like a ballerina. Slowly. One revolution in $1 \over 0.56$ sec. A field of around 0.5 Gauss (depending on orientation) goes through one period in that 0.56 sec. Probably not very helpful, though.

What I mean to say is that $10^{-8}$ Gauss is excruciatingly small. (Big physics experiments work with several Tesla (1T = 10000 Gauss).
There must be something awry there, but I don't have access to the original article.

 if your target mass is on a molecular scale, shouldn't the target length be on such a scale too ?

PS your ' 2.4 $10^{-3}$ ' turns at 25 A give the 'same' field as 2.4 turns at 25 mA

@BvU

Yes, understood, a nice idea!

It seems that low level emfs do actually have quite an effect, as the paper i referred to has found. Here is some background:
https://www.drpawluk.com/health/electromagnetic-fields-and-the-heart/
Maybe i am approaching this from the wrong direction. Is there a standard number of turns and wire size used when winding a pair of Helmholtz coils? Perhaps i should use that and then vary the current to produce the required field strength.
I would really like someone to check the results of the 2 initial equations though. Any takers?
P.S. I have a copy of the manuscript referred to that i originally downloaded. It seems now that a registration or fee is required to view it. Would i be breaking copyright to post a link to my own copy?

BvU
Homework Helper
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Is there a standard number of turns and wire size used when winding a pair of Helmholtz coils?
In physics school labs, Helmholtz coils are used in the Thomson e/m experiment (google e/m experiment or e/m apparatus !) Typically 100 turns, and a few A. A bit smaller than what you intended (but do you really want these EMF influences in a large volume if they have such effects ? -- in post 1 you seem to think of a centered field (do you mean focused, concentrated, localized ?), but Helmholtz coils are popular because they generate a fairly uniform field )

In your link they mention 2000 Gauss - a long way from $10^{-8}$ !

I would really like someone to check the results of the 2 initial equations though. Any takers?
You mean other checkers ?
1) mc(2) = q(j) v B L
where m =target molecule mass = for vasostatin-1 mol weight of 7KD = 7000 x 1.169 x 10(-24)gm
c =velocity of light =2.99 x 10(10)cm/sec
q(j) = 1 ab-coulomb
v = earth's orbital velocity = 3 x 10(6)cm/sec
L =target linear dimension = 1.73 x 10(2)cm
B =magnetic amplitude in Gauss
I pointed at target molecule for m and target length for L.
I could also ask: what on earth has the earth orbital velocity to do here ?
And what can possibly have 1 ab-coulomb (do me a favor: use Coulomb) charge ? It is gigantic.

I don't understand the expression. All I can do is check dimensions -- they seem to match. And read the source -- which I can't.
But it sure looks weird. $mc^2$ is energy. $qvB$ is a force -- but a force perpendicular to v. So $qvBL$ has the same dimension as $mc^2$

In short: I don't believe for a moment this is is right.
If I were you I'd forget this Jerry Jacobson altogether.

Copyrights ? I have no idea. Read the small print perhaps ? But you could retype the relevant passage, I am pretty sure.

jim mcnamara
Mentor
Interesting. Jacobson (a dentist BTW) has one publication. That I can find. He has two patents on the use of low-level EMF on various maladies. All patents issued prior to the publication which came out in 2001.
@BvU I would second your opinion. At best, the publication listed here appears to be a limited clinical trial. And it seems to be applying a magnetic field for osteoarthritic problems.

Low-amplitude, extremely low frequency magnetic fields for they treatment of osteoarthritic knees: A double-blind clinical study
JI Jacobson, R Gorman, WS Yamanashi… - … Therapies in Health …, 2001 - search.proquest.com
Abstract Jacobson et al present a study determining the effectiveness of low-amplitude,
extremely low frequency magnetic fields on patients with knee pain due to osteoarthritis.
They conclude that low amplitude, extremely low frequency magnetic fields are safe and ...
Cited by 108 Related articles All 5 versions Cite Save

Magnetic field generating device and method of generating and applying a magnetic field for treatment of specified conditions
JI Jacobson - US Patent 6,099,459, 2000 - Google Patents
A magnetic field generator device includes a signal generator capable of operating within
predetermined parameters, an attenuator is connected to the signal generator and to
helmholtz coils to transmit and attenuate the signal from the generator to the coils to ...
Cited by 49 Related articles All 2 versions Cite Save
Method for ameliorating the aging process and the effects thereof utilizing electromagnetic energy
JI Jacobson - US Patent 6,004,257, 1999 - Google Patents
A method and apparatus for ameliorating the aging process and the effects of aging and
maintaining the integrity of health is provided. The method includes subjecting biological
systems to alternating and steady magnetic fields having flux densities ranging from 10-6 ...
Cited by 42 Related articles All 2 versions Cite Save
BTW - the last patent seems 'interesting' - a cure for aging.

Lest you think I'm being silly, consider:
US Podiatrists sometimes use a strong magnet for 24 hours after foot surgery on a diabetic patient, to
speed healing. But this is based purely on clinical observations. Note the word 'strong' and the fact that the magnet is in very close proximity to the wound.

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Here is a link to the paper i referred to
http://www.thatchmasters.ie/Astro/Document.pdf
As it was published in the medical literature I thought it was legit. Do you think its all bullology?
As a sufferer of AFib myself, i tend to clutch at any straw like the drowning man!
Cheers
John
P.S. @BvU, thanks i didn't realize that you had worked through the results i obtained

BvU
Homework Helper
2019 Award
Great. The link shows you faithfully reproduced JJ's 'writing' on p19. Interesting is that his ref 19 (surprise: by JJ!) is also available on the net. For convenience he there rewrites three hundred years of physics development for his purposes and has no problem equating coulombs to kilograms: 1 coulomb is 6e18 electron charges, one electron is 1e-30 kg, so clearly 1 coulomb is 6e-12 kg. And so on. I don't believe my eyes.

Ok BvU, well it seems I have wasted your time.
It shows how easily I can be baffled both by accepting published science papers, and by my limited understanding. Result: a couple of coils and a frequency generator ain't going to fix my arrythmia!