Fig. 3

a, b Altitude profiles of the collision rate per electron for the cases of mono-energetic precipitation of 1, 4, 10, and 40 keV electrons, whose initial pitch angle is (a) 0 and (b) 70 degrees, at an altitude of 400 km. Solid and dotted lines show the simulation results with and without mirror force, respectively. c, d Total number of collisions occurred through the mono-energetic precipitation of (c) 1 keV and (d) 40 keV electrons as a function of the initial pitch angle at 400 km. The simulation results with and without mirror force are shown in blue and red solid lines, respectively