Demonstrating Ring Currents in a Planeterrella Device: Experiments and Modeling.

Plasmas confined in a dipole magnetic field give insight into the basic physics describing how planetary magnetospheres behave and evolve over time. A laboratory Planeterrella setup is used to visualize ring currents ~~\textbf{~}through light emission generated by impact excitation, ionization, and recombination processes.~The Planeterrella device consists of a vacuum chamber with a 0.5 Tesla Neodymium bar magnet embedded within a biased aluminum sphere. The bar magnet combined with the potential difference between the biased sphere and the grounded chamber subject the charged particles to a vertically oriented magnetic dipole field and a radially inward electric field. Low pressures (\textasciitilde 400 mTorr) paired with applied voltages yield visible plasma ring currents. For the detailed analysis of these experiments, a Runge- Kutta-based Monte Carlo Collisional (MCC) algorithm was developed to follow the motion of electrons within ~the electromagnetic fields and track their collisions with ~neutral \textunderscore \textunderscore $_{\mathrm{2}}$ and \textunderscore \textunderscore $_{\mathrm{2}}$ particles. The MCC algorithm successfully reproduced the two visible rings.~