Fig. 1. (a) Required T_r (red curve) on the capsule of a high-foot scheme and the derived laser pulse (black curve) from 2D simulations for a 2-LEH spherical hohlraum with Φ_H = 8.8 mm and Φ_LEH = 2.2 mm. Only the prepulse (black solid curve) is considered in this experiment. (b) Post-processed time-dependent positions of plasma interface with electron density N_e = 0.1N_c, 0.2N_c, 0.6N_c, and N_c and positions of 50% peak x-ray emissions with energies between 0.8 and 1 keV or above 1.8 keV. The pink region is the laser channel. (c) Schematic of laser beam configuration and ignition-scale 2-LEH spherical hohlraum. The laser beams at 55° (orange) have a 1 mm diameter round shape at the LEH, and those at other angles have a 0.5 mm diameter. (d) Initial fields of view of the six flat-response x-ray detectors (FXRDs) and filtered M-band x-ray detectors (MXRDs), with the spots on the wall representing the laser depositions.

Fig. 2. (Left) Time-resolved raw images from an x-ray framing camera (XFC) at four different times and for two x-ray energy ranges of 0.8–1 and 2–3 keV for shot SGIII20170323148 with 1.4 mm diameter LEHs (upper) and shot SGIII20170324150 with 2 mm diameter LEHs (lower). (Middle) Drive laser power (light cyan dashed curve) and T_r (solid curves) with an error bar of 3% for shots SGIII20170323148 (upper) and SGIII20170324150 (lower). The small images match those on the left, except that the upper ones at 2.5 and 5.5 ns are for shot SGIII20170323149. (Right) Time-dependent LEH radius, defined as the half peak width of x-ray emissions of 0.8–1 keV, from XFC images (symbols with error bars of ±75 µm) and from post-shot 2D simulation (orange solid line) for shots with 1.4 mm diameter LEHs (upper) and 2 mm diameter LEHs (lower), with the red dashed line indicating the laser beam size. The mode 1 azimuthal asymmetry of the XFC images is due to the axis deviation between each pinhole and the XFC and to the axis deviation between the XFC and the target, which are considered in the error bars.

Fig. 3. (a) Time-integrated x-ray image at 2–3 keV observed by the pinhole camera at 16° from the upper side and (b) its field of view for shot SGIII20170323149 with 1.4 mm diameter LEHs. (c) and (d) Corresponding image and field of view for shot SGIII20170324150 with 2 mm diameter LEHs. The red dashed circle is the LEH edge and the yellow dashed circle is the outer boundary of the 1 mm diameter laser beam. Note that the size scales of the two images are different.

Fig. 4. Temporal behaviors of the M-band fluxes measured by the six MXRDs for shots with Φ_LEH = 1.4, 1.6, 1.8, 2, and 2.4 mm, with an error bar of 10%. The burrs on the curves are due to diagnostic noise at low fluxes. Note that the flux scale for Φ_LEH = 1.4 mm is different from the others.

Fig. 5. Temporal behavior of T_r (solid curves) derived using the measured fluxes from six FXRDs for shots with Φ_LEH = 1.4, 1.6, 1.8, 2, and 2.4 mm. The laser power (light gray dashed lines) is shown for reference.

Table 1. C_lm, ϵ_rms, E_aL, E_L, and LEH loss of an octahedral hohlraum with R_H = 4R_C for the CH Rev5 capsule, with Φ_LEH varying from 1.6 to 3.6 mm. Here, the LEH loss is the amount of input laser energy lost via the LEHs and is given by E_loss/η_aLη_LX. In each case, the input laser energy E_L is chosen to give a radiation temperature of 300 eV.

Table 2. C_lm, ϵ_rms, E_aL, E_L, and LEH loss of an octahedral hohlraum with R_H = 5R_C for the CH Rev5 capsule, with Φ_LEH varying from 1.6 to 3.6 mm. The LEH loss is the same as in Table I, and is given here for comparison with E_L.