1b. If G < 1 is the final result of the National Ignition Campaign (NIC) and follow-on campaigns after some reasonable period of scientific testing, then other drive approaches should be investigated as planned.

1c. The diode-pumped solid-state laser is optically very similar to the flashlamp-pumped NIF laser and so experiments on NIF will define future expectations for indirect drive with a diode-pumped laser. Assuming G > 10, before commitment to an FTF or DEMO, the following achievements will be necessary simultaneously in one laser IRE device, for instance,

— Energy in the 5 kJ range in the ultraviolet as planned.

— Efficiency >10 percent with 15 percent goal in UV.

— Repetition frequency >5 Hz, with clear technical extension to >15 Hz.

— Life test to >107 pulses, with clear technical extension to >109 pulses using the same medium.

1d. A chamber design with life expectancy of >108 pulses must exist for the indirect-drive threat spectrum and the chamber design to include final optical elements.

1e. Target fabrication must project to the precision and economy required of reactor operation.

Direct-Drive Target with Diode-Pumped Laser: Pre-conditions for FTF or DEMO

As with indirect drive, the diode-pumped laser will be optically very similar to the flashlamp-pumped NIF laser, and so laser performance on the NIF will define future expectations for direct drive with a diode-pumped laser.

Regardless of the outcome on indirect drive, even in the case that reactor-scale gain is achieved (1a above), the NIF laser should be used to study direct-drive targets, as planned.

Polar direct drive (PDD) is an interim approach to spherical direct drive (SDD) that employs the existing NIF beam ports. However, ignition with PDD is uncertain owing to likely laser-plasma instability (LPI) differences between the “equatorial” and the more polar beams. Polar direct drive may be a valid test bed for a preview of spherical direct-drive interactions on the NIF laser.

2a. In event 1b above, with G < 1 in indirect drive at the end of the ignition campaign, NIF should be upgraded as planned for PDD studies (2017) with beam smoothing (estimated $30 million for materials) and employed in a study of PDD physics at reactor plasma-scale size. If modeling of the results with validated codes



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