Recent content by craq

Thanks for all your replies. A couple were really enlightening. I've been through the forum now and looked at Tachyons, and a few more of the faster-than-light topics. Interesting stuff, but they don't seem to address my issue. Ok, particles with non-zero mass (real or imaginary) can't...

As I understand it (I don't study physics) any object with mass gets heavier and heavier as it accelerates, so it never reaches c. 'Light' has no mass, but can be regarded as essentially a fluctuation in the electric/magnetic field? From the definition of c^2=1/epsilon0/mu0, I interpreted...

I am building an ion beam, and the lens was intended to give real-time control of the beam diameter. Snell-Descartes is an interesting idea, possibly it solves much faster, but I can't immediately see how to code it. My goal was to visualise particle trajectories, so I find the acceleration...

Hi, this was just for a one-off design, so I had a look at the Simion demo but decided to write it myself in Matlab. Oversimplifying for a second, its just solving the Laplace equation to give the potential distribution and then the Lorentz equation for the motion of the particles (later in the...

Ok, I figured it out... just needed to let the laplace solver run to a few (thousand) more iterations to get a better solution for the voltage profile. My initial conditions are V=0 and the centre of the cylinder stayed pretty close to 0, giving a radially inwards electric field everywhere...

I'm trying to design an Einzel lens to focus an ion beam. The literature seems pretty consistent that the beam diverges in the first gap and converges in the second gap. (Gaps are between the three electrodes.) What I don't understand is that the potential is lowest at the centre of a...