Compute Electric Field from Electric Currents

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Discussion Overview

The discussion revolves around computing the electric field from electric currents using a specific equation. Participants explore the mathematical steps involved in calculating the components of the electric field (E_x, E_y, E_z) based on given parameters and equations, including the treatment of complex numbers and scalar products.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents an equation for computing the electric field and asks how to compute E_x, E_y, and E_z from it.
  • Questions arise regarding the interpretation of the symbol "|" and whether it represents standard notation.
  • There is a discussion about whether C_2 is a scalar and how to perform scalar multiplication with vectors.
  • Participants debate the correct approach to compute the expression (J*R|R*C_2) and whether it involves dot products or scalar multiplication.
  • Some participants suggest performing calculations with complex numbers and dropping the imaginary part if the result is not real.
  • Speculation occurs regarding the formula's origin and its implications for the calculations.

Areas of Agreement / Disagreement

Participants express uncertainty about the notation and the correct interpretation of the operations involved. There is no consensus on how to handle the computations, particularly regarding the symbol "|" and the treatment of complex numbers.

Contextual Notes

Limitations include unclear definitions of symbols and operations, as well as unresolved steps in the mathematical calculations. The discussion reflects varying interpretations of the equation and its components.

ggeo1
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Hello,

I have this equation that computes the electric field from electric currents.

E=-j*k_n (J*C_1- (J*R|R*C_2) e^ -j*k*R/4πR )

The data are:

k_n=377 , k=20.93 , R=Sqrt(3) ,J_x=0.72576821 ,J_y=0.03763659 , J_z=0.86104220 ,
C_1=0.999239077741 + 1 / 36.2518234024j
C_2=0.997717233223+ 3 / 36.25182344024j

R_x=R_y=R_z=0.57735026919


I have 3 questions.

1) From the above equation i must compute E_x ,E_y,E_z.
When i compute E_x i will compute J_x*C_1 - (J*R|R*C_2) ?
And specific: I will compute the J*R dot product as : J*R=J_x*R_x+J_y*R_y+J_z*R_z ?
Or only the J*R=J_x*R_x ?

2) The computation J*R|R*C_2 . How will i do the computation for the symbol ' | ' ?
I will compute the dot product , then the R_x*C_2 and then what?How to compute the whole
J*R|R*C_2 ?

3) How to deal with the C_1 and C_2? I mean they have the imaginary part in the denominator.What is the best approach?

Thank you!
 
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What does the symbol "|" represent? It does not look like standard notation.

C_2 is a scalar? In this case, both J*R and C_2 are scalars, and I would assume that you can just perform a scalar multiplication with your vector.

When i compute E_x i will compute J_x*C_1 - (J*R|R*C_2) ?
Don't forget the exponential which is multiplied with the latter term.

And specific: I will compute the J*R dot product as : J*R=J_x*R_x+J_y*R_y+J_z*R_z ?
You should do this, right.

3) How to deal with the C_1 and C_2? I mean they have the imaginary part in the denominator.What is the best approach?
1/10 does not look high, but I would perform the whole calculation with complex numbers. If the result is not real, try to find an interpretation - maybe you can simply drop the imaginary part.
 
Hello and thanks for the help.

C_1 and C_2 are scalars.

So, ok J*R=..=scalar.

But i can't understand how to do the (J*R|R*C_2) .
I will compute the J*R and then the R*C_2 , and then what?
 
I think it's

((J*R) *C_2 )*R , where R i will put R_x?

Then for E_y i will put R_y?
 
I would try to just multiply them as scalar*vector.

[tex](\vec{J}*\vec{R}|\vec{R}*C_2) \stackrel{?}{=} \left(C_2 (\vec{J}*\vec{R})\right) \vec{R}[/tex]

Edit:
I think it's

((J*R) *C_2 )*R , where R i will put R_x?

Then for E_y i will put R_y?
Should work.
It is speculative, and maybe you should check where the formula comes from.
 
Ok , thanks!
 

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