Delayed large-scale instabilities on Ti-coated duralumin conductors

The paper reports on experiments showing that duralumin conductors coated with Ti, compared to bare duralumin conductors, are able to delay and suppress the growth of large-scale instabilities on their surface. The experiments were performed on the MIG terawatt high-current generator at a current rise time of 100 ns and current amplitude of up to 2 MA, and the plasma and the instabilities arising at the conductor surface were recorded with a four-frame optical cameral at an exposure of 3 ns per frame. The most considerable effect of suppression was found for Ti coatings of thickness 20 - 70 mu m at a magnetic field of about 300 T. As the magnetic field at the conductor surface was increased to approximate to 400 T, the effect did occur but was less pronounced.