MAGNETIC-FLUX TUBE TUNNELING

We present numerical simulations of the collision and subsequent inter action of orthogonal magnetic flux tubes. The simulations were carried out using a parallelized spectral algorithm for compressible magnetoh ydrodynamics. It is found that. under a wide range of conditions. the Bur tubes can ''tunnel'' through each other, a behavior not previously seen in studies of either vortex tube or magnetic Bur tube interactio ns, Two conditions must be satisfied for tunneling to occur: the magne tic Field must be highly twisted with a held line pitch much greater t han 1, and the Lundquist number must be somewhat large. greater than o r equal to 2880. An examination of magnetic field lines suggests that tunneling is due to a double-reconnection mechanism. Initially orthogo nal field lines reconnect at two specific locations, exchange interact ing sections, and ''pass'' through each other, The implications of the se results for solar and space plasmas are discussed.