An electron lies at rest in the magnetic field of an infinite straight wire carrying a current I. At t = 0, the wire is suddenly charged to a positive potential ϕ without affecting I. The electron gains energy from the electric field and begins to drift:

• Draw a diagram showing the orbit of the electron and the relative directions of I, B, v_E, v_∇B, and v_R.
• Draw a diagram showing the orbit of an ion in the same conditions as above and the relative directions of I, B, v_E, v_∇B, and v_R.