Propagation of a streamer discharge in a magnetic field

In a magnetic field a Lorentz force acts on the motion of charged particles and thus influences the electrical discharge path of a streamer. Experimental observations in a 10 T magnetic field show that the trajectory of streamers in a knife-point geometry (with 15 mm gap) in nitrogen follows near the electrode a path that always makes the same Hall angle with respect to the electric field determined by the geometry. After about 7 mm the streamer deviates from the applied electric field, showing that the electric field of the streamer itself becomes dominant. From these observations the electron scattering time during streamer propagation can be obtained. Furthermore, these results strongly suggest that in this case photoionization is not very important for streamer formation.