Recent gasbag experiments on the Helen laser studied 2ω propagation and backscatter as a function of gas density. We present a comprehensive analysis of these experiments using HYDRA. Post-processed results agree well with experimental x-ray images showing stable laser propagation across the bag. The measured total stimulated Raman backscatter (SRS) increases with gas fill density up to n_e ≈ 0.08n_c, then decreases. Near-backscatter images show that the decrease in total SRS with increasing density is not due to scatter outside of the collection optics. SRS gain spectra calculated from the HYDRA results agree well with experimental streak spectra. The tilt and spread in wavelength of the spectra appear to be explained by gasbag hydrodynamics alone. Axial density gradients and laser pump absorption combine to limit SRS gain at high density.
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