The Ferranti Surge Absorber

The Ferranti Surge Absorber is use to minimize the steepness of a travelling wave.  The Ferranti surge absorber is made of a coil which is enclosed in a metallic cylinder which is grounded.   The metallic Cylinder is known as the dissipator.

The construction resembles an air core transformer with a low inductance primary and a single turn secondary short which is short circuited. 

When the wave reaches the Ferranti surge absorber, it induces an emf in the dissipator.  Energy is transmitted from the coil to the dissipator and expended as heat.  This reduces the steepness of the travelling wave.