Magnetic Energy of solenoid( u=m·B or u=B^2/4pi )

Thread starter sean1832725142
Start date Jun 21, 2017
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Energy Magnetic Magnetic energy Solenoid

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The discussion revolves around the confusion regarding which formula to use for calculating magnetic energy in a solenoid, specifically u=m·B or u=B^2/4pi. The participant notes that in Gaussian units, the electromagnetic field-energy density is expressed as u=1/8π (E^2+B^2). Clarification is sought on the appropriate formula for magnetic energy specifically in the context of solenoids. The participant is looking for guidance on the correct application of these formulas. Understanding the context and units is crucial for accurate calculations of magnetic energy.

Jun 21, 2017

sean1832725142

Hi,

I have a problem with the fomular
u=m·B
and
u=B^2/4pi
Since I want to calculate how many magnetic energy on a solenoid, I couldn't decide which fomular should I use.

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Jun 21, 2017

vanhees71

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In Gaussian units the electromagnetic field-energy density is given by
$$u=\frac{1}{8 \pi} (\vec{E}^2+\vec{B}^2).$$

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