Sorry, I am not a professional programmer. I do not have time to create an environment like phunland.
However, if you have a well defined case: for example: magnetic field produced by a specific current loop, or severla current loops. ...etc. I will try to help.

You are welcomed to check out [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=181.0]Magnetic field pattern for (line/ coil/ solenoid)[/url] or [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=198.0]Particles and Walls[/url]