Figure 1: The above rendering choice shows density (blue) and magnetic field strength (transparent yellow) isosurfaces for t=2, from a series of 11 snapshots. Fieldlines and vector arrows are also represented with white and deep red colour respectively. The brightness of the field lines represent the magnitude of the field. The brightest the lines the strongest the magnetic field. The field lines are running pretty much in parallel along the tubes and they "connect" the one with the other slightly. Note also the mass ejection that occurs between them (at the center of the figure). The magnitude of the magnetic field is 10% of the maximum and for the mass density is 89.8 % of the maximum value.
You could also check the evolution of the structures in time for the 1st, 4th, 6th, 8th and 10th timestep. Magnetic field magnitude is blue, mass density is transparent yellow (even in the last snapshot I have reversed the transparence in the colours), fieldlines are white - black (depends on the strength of the magnetic field) and arrows are green.
Magnetic Field Magnitude and Mass Density Evolution (for t=1 to t=10)
Figure 2: This "coctail" of IDL slices represents cut along z-axis + time evolution of the magnetic field magnitude (dark background) and the mass density (white background) of both tubes for 11 timesteps. Note that for t=1 the interaction between the tubes is weak and becomes more and more effective during the next timesteps. For t=6 the tubes are collided and for t>10 the long vertical tube is "destroyed" (violent interaction). There is no doubt that our initial setup choice (SIZE and OFFSET betwwen the vortex tubes) effects on the interaction between these tubes.