- #1
latentcorpse
- 1,444
- 0
for a constant magnetic field [itex]\vec{B}[/itex] everywhere, [itex]\vec{A}=\frac{1}{2} \vec{B} \times \vec{r}[/itex]
because (im not going to use vector notation to save time)
[itex]\nabla \times (B \times r)= (\nabla \cdot r)B + (r \cdot \nabla)B - (\nabla \cdot B)r - (B \cdot \nabla)r[/itex]
the first term gives 3B
the third term vanishes
the fourht term gives -B
so to get the answer i need the second term to vanish but i can't get it to go away - how do i do this?
because (im not going to use vector notation to save time)
[itex]\nabla \times (B \times r)= (\nabla \cdot r)B + (r \cdot \nabla)B - (\nabla \cdot B)r - (B \cdot \nabla)r[/itex]
the first term gives 3B
the third term vanishes
the fourht term gives -B
so to get the answer i need the second term to vanish but i can't get it to go away - how do i do this?