A phosphor screen is often used to image the incidence of a beam of electrons. In many cases, the luminosity obtained on the screen can be a quantitative measurement of the beam current or even of its energy. The situation is much more complex when the electron beam travels in the presence of a static magnetic field. In this talk, we will discuss the particularities of a beam of free electrons travelling under two perpendicular magnetic fields. The first one is axial, oriented in the direction of the travelling electrons. The second one is perpendicular to the direction of travel of the electrons and rotates uniformly 180º within a few centimetres (like a ‘virtual’ magnetic domain wall few centimetres wide). With the help of COMSOL simulations, by fitting the position and shape of the luminous spot on the phosphor screen, we will visualize the trajectory of the electrons and the effect of the electron-electron electrostatic interactions within the beam. Although we will talk mostly about the charge of the electron, at the end, we will give a ‘spin’ to the talk, so everyone feels more at home.

​ Plus d'information :https://www.spintec.fr/seminar-free-electrons-travelling-in-a-uniformly-rotating-magnetic-field/​