LLE Review 155
This volume of the LLE Review, covering April–June 2018, features “Observation of Nonlocal Heat Flux Using Thomson Scattering” which reports the first direct measurement of nonlocal heat flux in laser-produced coronal plasma using Thomson scattering. Both classical and nonlocal electron distribution functions inferred from the Thomson spectra are used to calculate the heat flux in the corona. The classical theory overpredicts the heat flux as much as a factor of 2 than the nonlocal theory toward the region of high temperature gradient.
Additional highlights of research presented in this issue include the following:
- An improved ray-based modeling technique of cross-beam energy transfer (CBET) at caustics is presented. The improvement is based on truncating the interaction length of incident rays in each cell using the geometrical caustic boundary information.
- A chromic-acid anodizing of aluminum is shown to dramatically increase the total quantity of tritium retained compared to unmodified aluminum, and is therefore not suitable for use in tritium environments.
- The effect of grating compressor misalignment in a chirped-pulse–amplification laser system is discussed. The degradation of pulse duration and focal spot size is studied by increasing the grating tip/tilt and in-plane-rotation error using a FRED–MATLAB optical compressor model.
- A new rate-doubled, low-jitter 10-GHz fiducial comb generator for precision optical timing calibration applications is described. This self-contained and portable unit will be useful for many optical timing calibration needs.
- Three types of damage-site morphology of laser-heated material are described, depending on the presence of defects, the location of the maximum electric-field intensity in the medium, and the laser pulse width. Mechanical and heat-diffusion models are adopted to describe the features of these damage sites.