Hi everyone, I've been looking for an answer online but can't find much written about this so I thought I'd ask the experts here!

I've been trying to simulate a particle spiralling around a force field by adding a force that's the cross product of the particle velocity and the field. The circle it makes gets progressively bigger though.

I've told this is probably the solver method, with Euler not being precise enough where there is a force changing between time steps.

So I'm trying to change the gas integrator inside the POP solver to one of the Runge-Kutta options but it's not updating the particle positions when I do this. I can see in the spreadsheet that it's calculating the force and velocity ok but the particle won't move.

Am I missing something obvious here??