Comparison of plasma formation at the surface of Tior Zr-coated copper conductors at magnetic fields of 300-400 T
Experiments on the skin electrical explosion of cylindrical copper conductors coated by a titanium or zirconium layer at a peak induction of the magnetic field up to 400 T were carried out on the MIG high-current generator ( I max ≈ ≈ 2.5 MA, τ ≈ 100 ns). Plasma formation on the surface of a conductor coated by ~ 50 μm of titanium or a zirconium starts at least ~ 400 ns later than that on the surface of a conductor without coating at the magnetic fields up to 300 T. With an increase in the magnetic field up to 350-400 T, the delay of the plasma formation at the surface of the coated conductor is about 35 ns. For both coating materials (Ti, Zr), the expansion velocity of the surface plasma is equal to ~ 2.7×105 cm/s.