Monte Carlo calculation of noise transport in electric and magnetic fields

In computing noise transport by the Monte Carlo technique, electrons, their two velocity components and emission times, are generated in a random manner. The electron equations of motion are integrated numerically to determine subsequent position and velocity coordinates of the electrons. In the first phase of the computer program initial conditions are specified in order to fill the diode. In the second phase the electrons drift according to the self-consistent space-charge fields. Under steady-state conditions data for the number of electrons and the velocity components are recorded for several sections of the beam and for several unit time intervals. Fluctuations are then calculated from the average values to compute the various noise parameters for particular sections of the beam. The current fluctuations are smoothed due to the presence of the potential minimum, although the velocity fluctuations are increased as the beam is accelerated which accounts for large values of noise figure, commonly characteristic of crossed-field devices. The over-all growth for the slow space-charge wave is larger than that for the fast space-charge wave in traversing one complete cycloid.