Ejs Open Source Magnetic Dipole Field Vector & Field Lines 3D Model Java Applet by Wolfgang Christian
original version from http://www.compadre.org/osp/items/detail.cfm?ID=12361
this version is slightly edited by lookang.

work in progress

/htdocs/ntnujava/ejsuser/14019/users/sgeducation/lookang/MagneticDipoleField3Dwee_pkg/MagneticDipoleField3Dwee.propertiesFull screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
Download EJS jar file(1162.6kB):double click downloaded file to run it. (23 times by 11 users) , Download EJS source View EJS source

Magnetic Dipole Field in 3D by Wolfgang Christian
The Magnetic Dipole Field Model displays the field lines and field vectors of a dipole located at the origin and oriented along the z-axis.

B = (mu0*m/4*PI)(1/r^3)[3*m cap* r cap)r cp - m cap]

In Cartesian coordinates, the position vector r is ix+jy+kz and the magnetic dipole moment m vector is km.  Perform the dot product gives the following magnetic vector components:
Bx = (mu0*m/4*PI) (3*z*x)/r^5
By = (mu0*m/4*PI) (3*z*y)/r^5
Bz = (mu0*m/4*PI)(1/r^3)[ (3*z^2)/r^2-1]

Drag the yellow handle in the 3D view {added slider and inputs field now by lookang for better control] to compute the B field passing through a point (x,y,z).  Select the field option to show the field vectors in plane that passes through the dipole.
The Magnetic Dipole Field Model was developed by Wolfgang Christian using the Easy Java Simulations (EJS) modeling tool version 4.3.  You can examine and modify the model for this simulation if you have Ejs installed by right-clicking within the program and selecting "Open Ejs Model" from the pop-up menu.

Information about EJS is available at: and in the OSP ComPADRE collection . http://www.compadre.org/osp/items/detail.cfm?ID=12361