Maxwell equations + scalar and vector potentials

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The discussion centers on the equation for the electric field derived from scalar and vector potentials in electromagnetics: \vec{E} = -j\omega\vec{A} - \nabla\phi. Participants clarify that j represents \sqrt{-1}, and the equation assumes a general vector potential where only its curl has been defined. It is suggested that if the vector potential is expressed as \vec{A} = \vec{A}_0 e^{-j\omega t}, it aligns with the provided equation. The conversation also touches on the relationship to Helmholtz's theorem, indicating that the formula satisfies specific mathematical conditions. Overall, the discussion aims to clarify the assumptions and implications of the equation in the context of electromagnetic theory.
JamesGoh
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Im doing some study on scalar and vector potentials in the area of electromagnetics, and the author of the book derived this equation

\vec{E} = -j\omega\vec{A} - \nabla\phi

where \vec{A} = vector potential and

\phi = scalar potential and

\vec{E} = time harmonic form of electric field

The author goes on to make a statement saying this may be a familiar result, however I am not sure exactly what he is referring to ?? Can anyone shed some light ?
 
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Looks like one of these.
What is j, is it \sqrt{-1}? Is a specific vector potential given (say, A \propto e^{-j \omega t}?)
 
The author probably assumes you have read an intermediate level EM textbook.
 
CompuChip said:
Looks like one of these.
What is j, is it \sqrt{-1}? Is a specific vector potential given (say, A \propto e^{-j \omega t}?)


j = sqrt(-1). The textbook assumes a general vector potential (where at this stage only the curl of the vector potential has been defined)
 
Well, as I said, the Maxwell equations contain
\vec E = \frac{\partial \vec A}{\partial t} - \vec\nabla\phi
so if A is something like \vec A = \vec A_0 e^{-j\omega t} then you would get what you posted. That's all I can guess based on your information,
 
Sorry, didn't notice your wikipedia link. Will look into it and get back to you !
 
i'm not quite sure about what j and omega presents,but the formula seems to be written in the form that satisfy helmhotlz's theorem,hope it help...
 
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