Earth conductivity

[FrankM]

While searching for info on electrical charge distribution at the earth's surface, I identified an application that uses the earth as a near perfect conductor.

 

When One Wire Is Enough (html)

Single Wire Earth Returns (1.534 MB pdf)

 

It is a working application that can't be disputed, but I cannot find a geophysics source that identifies the theory for the near perfect conduction. The pdf article notes that the engineers used 0.05 ohms/km at 50 Hz for the design model. All of my reference sources indicate that earth resistance is quite high. Am I missing something, as it seems the earth conduction is different from earth resistance?

 

Any sources for the earth conduction theory?

 

This entry edited to change way URL presented when forum files were restructured. (6-10-04)

[FrankM]

I want to add some information I received from another source that explains the fundamentals of earth resistance testing for establishing earth grounds. The article covers several of the testing methods and presents the theory why earth resistance is low (conductivity is high).

 

Earth Ground Testing

 

Page 8, Figure 9 states the decreasing resistance is based upon increasing concentric shells. In other articles, the terms "sphere of influence" and "hemisphere of influence" are used to describe the same reason for decreasing resistance. Old telegraph engineers used to say earth conductivity (near zero resistance) was because the earth acted as an infinite number of parallel resistors. The use of concentric shells or hemispheres to explain low resistivity is a new twist on that theory.

 

I have been searching geoscience and geophysics sources for tests that should confirm the theory, but have yet to found any. I find many articles where scientists are exploring the conductivity of various crustal layers, but this seems a mute point to explore if the power transmission system identified in the first post encounters essentially zero resistivity.

[Tormod]

I wish I could help you out here, but this is beyond me. Make sure you post any results if you find something.

 

Tormod

[FrankM]

The article in the following URL uses some strange terms, "dormant charge" being one.

 

EarthObservatory - Dormant Charges

 

The author of the article took a great deal of technical liberty in his made-for-public descriptions. Hidden in the statements implies that earth ground charges have great mobility and can be locally clustered, which is equivalent to atmospheric physicists models. I suspect the development of large charge differentials deeper in the crust are the result of a sustained piezoelectric event that creates a regional zone of charge separation.

 

These charges are not easy to pin down. They move with impressive speed, as fast as 300 meters (1,000 ft.) per second," he said.

 

I do not know how the speed was measured. The effect on the ionosphere suggests surface charge levels that are as extreme or greater than those that occur during an overhead atmospheric electrical event, but covering a greater area. The mobile charges and enhanced local charge density suggests that earth conductivity could change significantly in the area of these charges.

 

Are there any studies where the earth's electrical conductivity has been measured when it is reasonably assured there are areas of increased charge density (nearby thunderstorms)?

[Phire]

I'm curious. If the earth a near perfect conductor, would this mean we can pass electricity through it like a electrical wire?

[wavelength?]

The book: HARNESSEING THE WHEELWORK OF NATURE - TESLA'S SCIENCE OF ENERGY EDITED BY THOMAS VALONE,PH.D,PE has some very good information on ground conductivity.

[FrankM]

Originally posted by: Phire

I'm curious. If the earth a near perfect conductor, would this mean we can pass electricity through it like a electrical wire?

 

Actually, it is quite common to use the earth as a conductor. The first post on this subject cited the following URL,

 

When One Wire Is Enough

 

The first telegraphs used one wire and the return as earth ground. Many of the first rural telephones were one wire with earth ground return.

 

Atmospheric physicists state that the earth surface has a negative charge relative to the ionosphere, which implies there is a concentration of free electrons in the near crustal surface that counteracts the ionospheric positive charge. One of my questions is, how much do these extra free electrons contribute to earth conductivity in the upper crustal area?

[FrankM]

This adds additional information relative to my original inquiry concerning electrical charge distribution at the earth's surface.

 

The following report suggests that the "conductivity" in the induced charge area is substantially different from areas removed from the influence of the induced charge.

 

Induced Charge Conductivity

 

"The primary destination of the strike is the induced charge on the ground surrounding the strike point."

 

There was no mention of any attempt to measure the "relative" conductivity in the induced charge area.

 

Just how much is "earth surface conductivity" influenced by the presence or lack of "free electrons" induced by the ionospheric charge and changing overhead atmospheric electrical events? The induced charge can be either positive or negative depending upon the "overhead" charge.

[FrankM]

My post of 02/04/2004 04:57 AM identified a NASA article about "mobile charges" and related issues. A

question about "mobile charges" was brought up on another forum.

 

The ELFRAD technical forum (http://www.elfrad.org/ ) had identified unusually large "in-earth" pulses

that had opened fuses on an earth antenna protection circuit. There were a number of questions

concerning the source of the "pulse" and I mentioned that a "mobile charge" identified in the NASA

report could appear as a pulse to the receiver. Unknown to me, the author of the NASA report was a

"quiet" member of this forum, Friedemann Freund. The following is the discourse concerning the "pulses".

 

Some comments on the pulse that opened 250 mil fuses.

 

It has to be local to the site to pop the fuses, but the actual intensity, origin and

bounds of the pulse are unknown.

 

The following site discusses a NASA report on "mobile" charge clusters

moving through the earth.

 

http//earthobservatory.nasa.gov/Newsroom/NasaNews/2001/200112076296.html

 

A quote from the article, '"These charges are not easy to pin down. They move with

impressive speed, as fast as 300 meters (1,000 ft.) per second," he said.'

 

The article did not state how the "charges" were detected, but a fast moving charge

cluster could appear as a pulse to a detector in its path. The pulse could have a

different origin than what is being described in the NASA article. There are some complex

processes going on in the subsurface that we do not fully understand.

 

FrankM

 

The reply on the forum from Friedman Freund is as follows:

 

I'm responding to your message sent to the Elfrad group (of which I am

a happy, though mostly silent member). I want to clarify two things

that were mentioned in this 2001 piece with reference to my work

(1) the "impressive speed" of the positive hole charge carriers and

(2) how the speed was measured.

 

(1) Since 2001 we have done a lot of additional work along these lines

and seem to understand now that the "speed" is the speed with which the

signal travels, i.e. the speed with which a charge pulse travels. It is

NOT the drift velocity due to the physical displacement of the charge

carriers.

 

(2) The measurements were done during impact experiments where we shot

a projectile at rock cylinders or rectangular blocks of rock and

measured the time it took after the impact for the positive charge

cloud (several hundred mV) to reach a series of capacitive sensors.

When we used quartz-bearing rocks like granite we, the piezo-electric

response enabled us to "see" the passage of the P and S waves

(compressional and translational), which travel at close to 6 km/sec

and 3.4 km/sec, respectively. The propagation of the positive hole

charge signal was much slower.

 

I should note that I'll have the opportunity to repeat the impact

experiments in the near future and hope to thus learn more about the

elusive positive hole charge carriers in rocks.

 

I should also mention that I followed with great interest the damaging

EM "pulses of unknown origin", which Charlie reported. It's fascinating

and puzzling.

 

Friedemann Freund

 

What should be noted is that electron drift, the conventional process for conduction, is different from the

"charge" propagation noted in the NASA report. Note the statements, "The propagation of the positive

hole charge signal was much slower." and "the elusive positive hole charge carriers in rocks".

 

One of my earlier questions was ,"how much do these extra free electrons contribute to earth conductivity

in the upper crustal area?". Now I can add, "How much do the positive hole charge carriers contribute

t

[Freethinker]

In Electronics, we were told that "hole flow" and electron movement were two aspects of the same process. That as an electron flowed to fill the "next hole", that left a hole behind it. Like musical chairs.

 

Is "electron drift" more of an excess of electrons in larger qty in a given area and not a direct component of a conductive electron/ hole flow?

[FrankM]

This was a duplicate post as it did not seem to post when submitted, thus tried again, which is the next post.

[FrankM]

It seems that the earth does act like a semi-conductor, at times.

 

http://www.scec.org/instanet/01news/es_abstracts/ouzounov_freund.pdf

 

Electron drift is normally defined relative to the conductivity of a specific material.

 

An excess of electrons is the subject of my post of 04/10/2004 09:35 PM and the general subject of this

thread. The geophysics model of the earth-astmosphere interface suggests the existence of excess

free electrons but I have found no studies (measurements) that confirm this phenomena.

[FrankM]

I should not have used the term "existence of excess free electrons" in the previous post. What the

geophysics model suggests is that geological and atmospheric events cause a "concentration of free

electrons" or a "concentration of positive charge carriers" at specific sub-surface locations for the

duration of an event. These "concentrations" should alter the apparent earth conductivity and should

be measureable.

 

The normal clear air (ambient) "concentration of free electrons" at the near earth surface would be that

which is induced by the normally positive ionosphere. Geologic and atmospheric events can alter the

"ambient" level of free electrons, thus changing conductivity.

[kaywil]

I'm searching for references needed ascitations in a researchstudy,that clearly state that the surface of the earth has a negative charge. Some people refer to it asa slight negative charge.Guidance please.

Thanks,

Kay

[FrankM]

You can start with the definitions maintained at the TexasA&M site.

 

<a target=_blank class=ftalternatingbarlinklarge href="http://www.met.tamu.edu/personnel/faculty/orville/Glossary.htm">http://www.met.tamu.edu/personnel/faculty/orville/Glossary.htm

</a>

 

The terms air--earth conduction current and air--earth current state that the earth is negative

relative to the ionosphere. Using the various descriptive terms associated with these definitions and others

in the glossary in a search-engine should help identify further references.

 

The TAMU site is primarily dealing with meteorology, but many of the definitions are shared with atmospheric

physics.

[Tormod]

Sorry about the ads, Frank. I am simply trying out something on request from the ad agency. The problem is I have no idea what they look like since they obviously only show to people who are in the US. Could someone please send me a screen dump of what it looks like? It is not my intention to piss people off so if this is offensive it will be removed.

 

Only 5 words on each page should be marked, according to the agency.

 

Tormod

[FrankM]

The Edit process is now functioning normally.