Miniaturization of electron storage device

A scheme for setting up a small-sized table-top level electron storage device is proposed. Insulator pipe, electron reflecting mirrors and loose controlling enable a high-energy beam to be confined effectively along a polygonal, closed, short path. Moreover, self-field can cause a beam to be of a space-time varying shape and a finite real-space volume because the density cannot be negative-valued. This also favors a small-sized storage device.