Electrostatic deflection

The technique is called electrostatic because the strength and direction of the applied field changes slowly relative to the time it takes for the particles to transit the field, and thus can be considered not to change (be static) for any single particle.

For electrostatic deflection, the applied electric field is arranged so that it lies in the plane perpendicular to the initial direction of the stream.

The path the particles follow depends on their sideways acceleration and their velocity when they enter the deflecting field.

In these tubes the electric field is created by two sets of paired electrodes, mounted at right angles, that the electron stream flows between.

[1] In very high speed oscilloscopes, the deflection plates were often complex structures, combining a series of sub-plates with an electrical delay line.

However it was found by computation methods that deflection aberrations would be significantly reduced if the beam were injected offset toward the attracting plate.