Using STUD pulses to Control LPI Adaptively in Space and Time, Using Machine Learning and High Rep Rated Lasers: The Green Option for IFE

This presentation addresses the STUD pulse program [Afeyan09,10,13a,13b,14] for Laser-Plasma Instability (LPI) control. Spike Trains of Uneven Duration and Delay (STUD pulses) are a means of combining both deterministic and random techniques at our disposal to scramble the speckle patterns that impinge upon a High Energy Density Plasma (HEDP) where energy is deposited in laser-based IFE schemes. The idea is to combat memory build up inside the plasma which is inevitable when prolonged quasi-static irradiation patterns imprint their imperfections and vast fluctuations onto the plasma for durations very long compared to the typical growth rate of laser-plasma instabilities such as SRS, SBS), and TPD. The active memory buildup prevention is so that inside a single speckle or laser hot spot, growth is halted. And also, so that inter-speckle communication and multi-speckle self-organization is also halted. The active switching of the laser, on and off (say with a contrast of a 100 or more) in time on the ps time scale, deterministically, with intervals that are optimized to remove plasma memory, and scrambled randomly in space (resampled from the Poisson intensity statistics distributed speckle patterns) is the STUD pulse prescription.