[1] AstroShk-13A : February 28, 2013 Shock reflection phenomena relevant to astrophysical jets P Hartigan J M Foster, D Martinez K Yirak, B H Wilde, P A Rosen B Blue, R Paguio

[2] AstroShk-13A : February 28, 2013 Astrophysical jet : for example HH 47  Bright regions at working surface of some astrophysical jets might arise from irregular shock reflections (Mach stem) – Pat Hartigan (Rice), Adam Frank (Rochester) interest  Development of Mach-reflection shock already shown in AstroShk-12A, -12B experiments at OMEGA  Two experiments this week: – Cone-in-foam target (add further data points to previous work) – Gas-cell target (before Mach reflection in radiative shock, later in 2013)

[3] Laser –SG 1018 (drive) and SG1014 (backlighter) pulse shapes –12 P7 drive beams –No DPPs –7 backlighter beams onto two backlighter targets –SG8 DPPs –Typically, 50 ns backlighter 'delay' Diagnostics –TIM 1 : TTPS (backlighter for TIM5) –TIM 2 : XRPHC (monitor backlighter) –TIM 3 : XRFC + MPBL (backlit image of shock interaction) –TIM 4 : TTPS (backlighter for TIM3 or gas-cell target) –TIM 5 : XRFC + MPBL (backlit image of shock interaction) –TIM 6 : XRFC (monitor laser-entry hole) –Fixed XRPHCs AstroShk-13A: (a) Interaction of a shock with a Mach-stem-forming cone; (b) Shock propagation in a gas cell P7P6 Dual-axis x-ray backlight Mach stem Ablation-driven 'piston'CH foam Shock 10 targets Single-axis x-ray backlight Gas cell P7P6 Shock in Kr or Xe CH 'piston' in Au disc CH–gas interface 5 targets

[4] Previously : –The angle of shock incidence at the cone was varied –Changes of angle were used to investigate hysteresis 100 ns 40° 87 ns60 ns RAGE simulations by Kris Yirak, LANL Concave cone (maintains angle of shock interaction) Discontinuous change of angle # 63393, TIM5 # 63393, TIM3

[5] Mach-stem size vs. radial position on cone (effectively, vs. time and angle of incidence) Critical angle Mach-stem size vs. time and position

[6] 100 µm CHBr (1.22 g/cc, 2% atomic Br) 300 µm CH (1.06 g/cc) AstroShk-13A: –Reduced preheat: CHBr (6% Br) layer and aluminium glint-shield –Another cone angle 100 µm CH (1.06 g/cc) 300 µm CHBr (1.5 g/cc, 6% atomic Br) 0.1 µm Al February 2102September 2102: added more preheat shielding February 2103: another cone angle

[7] 10 ns 20 ns 30 ns 40 ns 3D RAGE simulations by Kris Yirak, LANL The AstroShk-13A gas-cell shots are a precursor to investigating Mach reflection in a radiative shock Gas-cell targets will investigate sensitivity of the Mach stem's formation to the effective polytropic index of the gas (determined in part by radiative losses) 3 atm. Kr or Xe gas fill