Measuring the electric field of the Earth

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SUMMARY

This discussion focuses on measuring the Earth's electric field using a setup involving two parallel metal plates, one larger than the other, and an oscilloscope. The method involves grounding the lower plate and insulating the upper plate, with the charge potential calculated using the formula $$V_{charge}=\frac{JA}{C}t$$, where J is the current density, A is the area, C is the capacitance, and t is the exposure time. The charge density $$\sigma$$ is derived from the oscilloscope readings and is related to the electric field E through the equation $$\sigma=\epsilon_0E$$. The viability of this method is confirmed, with considerations for capacitance based on the distance and size of the plates.

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jamie.j1989
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Hi, I'm trying to measure the electric field of the Earth using a simple set up and would just like some opinions on the viability and practicality of this method.

The set up is as follows, two parallel metal plates with one larger than the other, the larger one is placed over the smaller at a separation of d, and an oscilloscope. I plan to ground the lower plate and to insulate the higher plate from ground. The larger plate should acquire a potential of,

$$V_{charge}=\frac{JA}{C}t$$

In a time t.
This result was found at http://arxiv.org/ftp/physics/papers/0701/0701296.pdf page 3 equation (4).

where J is the current density with units $$Amps*m^{-2}$$,A is the area of the plate, C is the capacitance, t the exposure time. I'm assuming here that what they mean by capacitance of the plate is the plates intrinsic capacitance? Which I am unsure about how to calculate.

I then plan to discharge the higher plate to the lower, and obtain a value for $$V_{charge}$$ from the oscilloscope, I will then use

$$\frac{V_{charge}C}{A}=\sigma$$

Where $$\sigma$$ is the charge density of the plate, and

$$\sigma=\epsilon_0E$$

To work out the electric field E of the earth. I'm slightly unsure whether the physics is correct though?

Thanks for any help.
 
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It will depend on the distance between the plates and their sizes, but I would expect capacitance to be dominated by the volume between the two plates, similar to a usual parallel plate capacitor.

Looks right.
 
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