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Electron Drift
Posted May 24, 2024, 9:19 a.m. EDT 1 Reply
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Hi, I'm simulating the trajectories of electrons drifting in Ar under an electric field. One single electron is released in the centre of a cube filled with argon. The electric field is applied by defining a potential on opposite sides of the cube with an electric field strength of about 400 V/cm. The static electric field is then calculated using the Electrostatics Node. The Charged Particle Tracing Node is using then this field to apply an electric force to the electron which is released without an initial velocity. I have turned on Elastic Collisions with specification of a collision cross section. The electron gets accelerated in the field and collides with the background gas atoms. However, the electron does not seem to just get accelerated by the field and then decelerated by the collisions. It gets scattered in a way that it even goes in the opposite direction of the electic force and then collides with the wall, not getting close to the anode. I've added a picture of one trajectory, the elctron should move to the front surface of the cube but gets scattered to the right where it collides with the wall. Is there anything to be considered in this simulation case for example linking the electric field to the Time Dependent Solver of the CPT in another way? It seems unrealistic, that the electron gets scattered this way and is this less affected by the electric field.
Thank you for any help.
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That is a possible path for a charged particle subject to both an electric field and random scattering. Whether this is a typical or unusual path depends on the scattering mechanism and strength of the electric field.
You can think of the particle as subject to diffusion in transverse directions and diffusion plus drift in the direction of the electric field. When the contribution of drift is relatively weak the motion of the particle is...random.