Stephan Huller

ABSTRACT We will present theoretical and computational results on Brillouin interactions between two beams in co-, counter-, and orthogonal propagation geometries. The beams will be structured (with speckle patterns), the plasma will have inhomogeneous flow including the Mach -1 surface. As the growth rate of the instability surpasses the natural frequency of the ion wave, the strong coupling regime (SCR) is reached, where reactive quasi-modes with intensity dependent frequency shifts result. This is especially true in laser hot spots. We trace the consequences of operations in this regime with different damping rates on the ion acoustic waves. We consider convective and absolute instabilities as well as the design of experiments which could examine these new regimes of instability behavior with new 10 psec time resolved diagnostics. Whether well enough conditioned beams can result after 10's or 100's of pairwise crossings in direct and indirect drive ICF configurations, and whether SRS can thus be strongly suppressed downstream, remains to be demonstrated. But the prospects exist for such new paths to instability control in a staged manner before STUD pulses are implemented.-

ABSTRACT The propagation and stimulated scattering of intense laser beams interacting with underdense plasmas are two important issues for inertial confinement fusion (ICF). The purpose of this work was to perform experiments under well-controlled interaction conditions and confront them with numerical simulations to test the physics included in the codes. Experimental diagnostics include time and space resolved images of incident and SBS light and of SBS-ion acoustic activity. New numerical diagnostics, including similar constraints as the experimental ones and the treatment of the propagation of the light between the emitting area and the detectors, have been developed. Particular care was put to include realistic plasma density and velocity profiles, as well as laser pulse shape in the simulations. In the experiments presented in this paper, the interaction beam was used with a random phase plate (RPP) to produce a statistical distribution of speckles in the focal volume. Stimulated Brillouin Scattering (SBS) was described using a decomposition of the spatial scales which provides a predictive modeling of SBS in an expanding mm-scale plasma. Spatial and temporal behavior of the SBS-ion acoustic waves was found to be in good agreement with the experimental ones for two laser intensities.

Unbeknownst to most, in June of 1983, Quentin Quesnell made a visit to Jerusalem in order to personally inspect the Mar Saba document known as the Letter to Theodore. This is significant because it adds Quesnell to a small group of people who have testified to have seen the Letter to Theodore in person, and an even smaller group who have commented on its appearance and contents first-hand. Following Quesnell’s death in 2012 many of his personal belongings were acquired by Smith College (Northampton) and recently released to the public for viewing. Among Quesnell’s belongings was a journal full of notes, along with photos and letters to his wife Jean Higgins, all relating to Morton Smith’s discovery of the Letter to Theodore at Mar Saba and to Quesnell’s 1983 visit to Jerusalem. On the basis of these documents the following article offers a summary of Quesnell’s part in the debate over Smith’s discovery and a report of his inspection of the manuscript.