Welcome to the Magnetic Field Applet This applet shows interactions between moving charges. It shows with a system of two wires why magnetic fields must exist in order for the postulates of relativity and charge invariance to be consistent with one another. Instructions: Java TA will guide you through the steps to take with this applet. Features: Wire 1 Frame: Boost into the Wire 1 Frame from the previous Frame Wire 2 Frame: Boost into the Wire 2 Frame from the previous Frame Lab Frame: Boost into the Lab Frame from the previous Frame Go/Stop: Start/Stop the representation of the current and charges Java TA: Start Java TA Next: Step Java TA Sync Speed: Make both wires have the same electron speed Anti Sync: Make both wires have equal and opposite speeds Wires can have the same current with different drift velocities, in this applet, the electrons are moving at high speeds to show the relativist effects, but the effects are exactly the same at lower speeds. *This applet is only a representation and approximation. Physics 1 | Java Applets Questions or comments? Send Email to phys1@cco.caltech.edu