Cross product evaluation (for the Lorentz Force).

AI Thread Summary
The discussion centers on calculating the cross product of electric and magnetic fields, specifically \(\vec{C} = \vec{E} \times \vec{B}\), within the context of the Lorentz Force. Participants express confusion over the derivation of related equations and seek clarity on the practical application of these concepts. A standard method for calculating the cross product using components is suggested, emphasizing that this information is widely available in textbooks and online resources. The conversation takes a personal turn, with one participant expressing frustration towards another, leading to the closure of the thread. Overall, the thread highlights the need for clear explanations in understanding complex physics concepts.
rogerk8
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Let's say we have:

\vec{E}=E_x\vec{i}_x+E_y\vec{i}_y+E_z\vec{i}_z

and

\vec{B}=B_x\vec{i}_x+B_y\vec{i}_y+B_z\vec{i}_z

and the Lorentz Force

0=q(\vec{E}+\vec{v}X\vec{B})

which due to

\vec{E}X\vec{B}=\vec{B}X(\vec{v}X\vec{B})=vB^2-B(\vec{v}\cdot \vec{B})

and transverse components only, gives

v_{gc}=\frac{\vec{E}X\vec{B}}{B^2}

where Vgc is the guiding center drift of the charged particles in a magnetic field with an electric field.

My question now is how to calculate

\vec{C}=\vec{E}X\vec{B}

I could have chosen pure math for this but I'm tired of theory that is hard to see the practical use of.

So what is C, with my definitions of E & B?

And how do I calculate it (the manitude and resulting direction is easy but I whish to see it in math)?

Does anyone want to help me refresh this knowledge?

Roger
 
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rogerk8 said:
which due to

\vec{E}X\vec{B}=\vec{B}X(\vec{v}X\vec{B})=vB^2-B(\vec{v}\cdot \vec{B})
I don't understand where that equation comes from.
My question now is how to calculate

\vec{C}=\vec{E}X\vec{B}
With the standard way to express the cross-product via components. You can find the formula in literally every textbook, in all the wikipedia articles and in thousands of other websites related to the cross-product..
 
mfb said:
I don't understand where that equation comes from.
With the standard way to express the cross-product via components. You can find the formula in literally every textbook, in all the wikipedia articles and in thousands of other websites related to the cross-product..

Simple, the equation comes from

\vec{E}X\vec{B}=-\vec{B}X\vec{E}

Please don't answer (or whatever you think you are trying to do) any more of my posts.

I don't like you.

/Roger
 
rogerk8 said:
Please don't answer (or whatever you think you are trying to do) any more of my posts.

I don't like you.

You don't like being reminded of reality by a professional working physicist? Hmm
 
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Roger has left the building, so this thread is now closed.
 
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