Current pulse in the graphite wire

1. Goran Skoro Current pulse in the graphite wire

2. LS-DYNA simulations Graphite Initial temperature = 500 C Geometry • 3 cm long wire • Radius [mm]: 0.3, 0.5, 0.75, 1, 1.5 Loads • Current pulse length: 800 ns • Current pulse length: 400 ns (same shape) strain • Energy density -> temperature rise; • Lorenz force induced pressure wave.

3. In the graphite wire case, Lorenz force plays equally important role as thermal stress Stress in the T2K target 0.3 mm radius wire; 800 ns long pulse 0.3 mm radius wire; 400 ns long pulse 0.5 mm radius wire; 800 ns long pulse Peak current [A] Results Peak von Mises stress [MPa] Stress as a function of the peak current in the graphite wire (operating at 500 C) LS-DYNA

4. 0.5 mm radius Results Von Mises Stress LS-DYNA

5. 0.5 mm radius Results Radial velocity LS-DYNA

6. Peak current [A] Stress in the T2K target 0.75 0.3 0.5 1.5 1 Results Peak von Mises stress [MPa] Stress as a function of the peak current and the graphite wire radius [in mm] fixed pulse length = 800 ns LS-DYNA

7. Peak current [A] T2K (0.75 MW) T2K (4 MW) T2K (2 MW) 0.75 0.5 0.3 1.5 1 Results Peak von Mises stress [MPa] Stress as a function of the peak current and the graphite wire radius [in mm] fixed pulse length = 800 ns LS-DYNA * * * Stress is calculated in the 3cm diameter, 90cm long graphite target.

8. Peak current [A] T2K (2 MW) T2K (4 MW) T2K 0.75 0.5 0.3 1.5 1 Results T [K] Temperature rise per pulse as a function of the peak current and the graphite wire radius [in mm] fixed pulse length = 800 ns LS-DYNA T is calculated using the radial current penetration/time formula

9. Peak current [A] T2K (2 MW) T2K (4 MW) T2K 0.75 0.5 0.3 1.5 1 Results T [K] Temperature rise per pulse as a function of the peak current and the graphite wire radius [in mm] fixed pulse length = 800 ns LS-DYNA T is calculated using the radial current penetration/time formula