Let me know all the parameters you have set for your simulation.

I do not know how to help you if I do not have any information about the simulation from you!

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Am studying the motion in very small period of time and calculate the vector of velocity and accelerate every moment

then I can calculate the position of the particle in this moment then I draw it ....

in the Gap I need to know the electric filed to calculate the accelerate vector acc = (q.E)/m

and I need the proton mass and charge ( I know them but they are so small that I couldn't represent them ..

in the Dee I need to know the magnetic filed to calculate the accelerate vector acc= (q.vB)/m ..