oscillate

the magnetic field oscillates in sympathy.

On an oscilloscope, you can see an electrical current oscillate up and down.

the play oscillates between third-person narration and monologue.

it oscillates in a plane at right angles to the cam axis.

Definition form Wikipedia: A degauss causes a magnetic field to oscillate rapidly, with decreasing amplitude.

The temperature at Earth's exobase oscillates but is typically about 1,000 kelvins, implying that hydrogen atoms have an average speed of five kilometers per second.