Reconnection of orthogonal (NN6) B_axial=1+cos(r*pi/R) flux tubes

Lundquist number S=R*v_A/(pi*eta)=3750, vs S=375

Initial peak velocity magnitude: v_A/10 as opposed to v_A/5, or v_A/20

Field in vertical tube runs top to bottom, in horizontal tube runs left to right (so mutual helicity is negative, reconnection should generate left handed twist).

Movie of fieldlines running through lagrangian trace elements placed in the plasma.

Only fieldlines running through elements initially in the vertical flux tube are shown.

The horizontal flux tube is in front of the vertical flux tube from this viewpoint.

Fieldline area at any point along the fieldline is proportional to |B| there. Any part of a fieldline at |B| less than 1/10th of the global maximum is not plotted.

Note that the movie frames were made more frequently near the peak of the reconnection, at other times frames are replicated so that the movie plays at a uniform rate.

Isosurfaces of B²=B²_max/9 (not normalized)

tv_A*pi/R=[0,170,350],

tv_A*pi/R=[450,550,870]

Fieldline snapshots from movie at same times as isosurfaces above.

My guess as to why the flux is all swept away from the center of the box at the end, leaving what looks like a lot of bent fieldlines, is that the stagnation point flow used to drive the two tubes together is responsible.

Energy vs time for the reconnection simulation and the reference simulations. The reference simulation is a single tube and the same S with no initial velocity.

Ratio of magnetic energy and current of reconnection simulation to that of the reference simulation.

Eparallel: global min of J.B/|B| normalized so that the peak is at 1. The global max peaks at ~1/3 this amplitude, and is much noisier. This curve is rougher than most, likely because data is taken only every 500 steps, vs every 10 steps for the other data plotted here, and because it measures a peak rather than a global average.