Figure 2
From: A new approach for fast field calculation in electrostatic electron lens design and optimization

A typical rotationally symmetrical electrostatic lens system in 2D. The z-axis is the axis of rotational symmetry.
From: A new approach for fast field calculation in electrostatic electron lens design and optimization
A typical rotationally symmetrical electrostatic lens system in 2D. The z-axis is the axis of rotational symmetry.