# Magnetic Vector Potential

1. Sep 30, 2004

### sinyud

How do you get the B field from the magnetic potential?
I tried converting the curl into matrix format, but the corresponding matrix can't be inverted.

2. Sep 30, 2004

### Tide

It's just the curl of the vector potential:

$$\vec B = \nabla \times \vec A$$

I'm not sure what you're tyring to do with it.

3. Sep 30, 2004

### sinyud

I got it backward. How do you the A field from a B field?

4. Oct 1, 2004

### Tide

Oh! Well in that case ... it depends on what problem you're trying to solve. Check with a good E&M book for some discussion on Green's functions. That might help. It's been a while since I worked with that so I'd have to review it myself.

5. Oct 1, 2004

### Dr Transport

$$\vec{A} = \pm \frac{1}{2} \vec{B} \times \vec{r}$$ if memory serves me correctly.....

6. Oct 1, 2004

### Tide

Thanks, Dr. T! Sinyud could easily check that by calculating the curl.