I started creating a library of free brushes for Photoshop. One of the brush sets consists of high resolution lightning bolts that would be ideal for depicting mag energy streams. The lightning bolts even have a glow around them and they look just excellent. Just download them if you want to try them out:

Click here to get the lightning brushes

Click here to see more brush sets

Click here for installation instructions for brushes

I plan to add more brush sets over time, so check the site periodically to see more.

Have fun!