Reconnection Spreading Between Non-Parallel Flux Ropes in 3D Simulations of the WVU PHASMA Experiment

Magnetic flux ropes are columns of plasma with axial and azimuthal magnetic fields and are commonly observed in the solar corona. The PHAse Space MApping (PHASMA) experiment at West Virginia University generates flux ropes in the lab to study their dynamics and how they reconnect. Two flux ropes are created using pulsed plasma guns in a strong background magnetic field. The flux ropes are fixed in space at one end (the plasma gun end) and the other end of the ropes terminates on a conical anode, which introduces a small degree of tilt between the two flux ropes. In the experiment, the flux ropes rotate around each other and move towards and away from each other throughout the discharge. Reconnection occurs in the region between the ropes during the "pull" and "push" phases of the relative motion of the ropes. Here, we present the 3D electron-magnetohydrodynamics (EMHD) simulations of the PHASMA device with experimental parameters. We use the F3D code with reconnecting flux ropes tilted at an angle, just like in the experiment, and find that reconnection spreads in a zipper-like fashion. The dynamics depend on the axial magnetic field strength and the ropes fully merge if the axial magnetic field is less than ten times the reconnecting field. We perform a parametric study as a function of the axial magnetic field and compare it to the laboratory observations.