Motion of a charged particle in the electric field of a uniformly charged finite wire

A recent article¹ in this Journal discussed the motion of a charged particle in the magnetic and electric fields of an infinite wire, finding an interesting class of “trapped” motions about the wire. The more realistic case of a finite wire/rod with uniform electric charge density also leads to “trapped” motion^2,3 (a kind of electric bottle), as can be seen in a delightful video taken at the NASA space station.⁴