Guide-field induced halting of magnetic reconnection in laboratory experiments

We conducted a laboratory experiment using two high-power lasers focused at two neighbouring points in order to generate two magnetic ribbons expanding fast toward each other. By tilting one target with respect to the other, we can generate a weak out-of-plane magnetic guide-field. Doing so, we observe an unexpected slowing down or even halting of the reconnection compared to the case when no guide-field exists . Concomitantly, we observe a delayed heating of the plasma in the reconnection region and supersonic and super-Alvenic outflows ejected from the reconnection layer. Through numerical simulations, we find that there is a destabilization in the quadrupolar structure of the magnetic field, which contributes to the changes the rate of reconnection.