Interaction bet electron and RF field in magnetron

[koushikr_in]

In magnetron it has been mentioned that electron interacts with stationary RF field.

Can somebody explain the statement clearly?

 

[flatulent]

The electrons go out radially from the central cathode to the surrounding anode. There is a perpendicular steady magnetic field usually caused by permanent magnets. This puts a force at right angles to the electron velocity. This makes them go in circle segments.