This influence on the speed of an ion is known as the "Asymmetry effect" because the ionic atmosphere moving around the ion is not symmetrical; the charge density behind is greater than in the front, slowing the motion of the ion. The time required to form a new ionic atmosphere on the right or time required for ionic atmosphere on the left to fade away is known as time of relaxation.
The influence on an ion's speed due to the asymmetrical nature of its surrounding ionic atmosphere, leading to slower motion, is called the "Asymmetry effect." The time it takes for a new ionic atmosphere to form or for the existing one to dissipate is known as the relaxation time.