Figure 2: Plasma characterization.
From: Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter

(a) Raw interferometry data for the plasma for t=11 ns (right), compared with the reference measurement (left). The target surface is located on the left side of each picture. (b) Comparison between measured and simulated free electron density (ne) profiles along the ion axis (x) for t=7 and 11 ns respectively. Experimental error bars, of approximatively 20%, are not represented. (c) 2D map of the simulations of the free electron density (ne) for t=7 ns, in units of cm−3 and represented in logarithmic scale. The solid arrow stands for the ion axis (1D plasma profile) used in the energy-loss calculations throughout the paper. The dotted arrows delimit the transversal region considered for the energy-loss calculation using a 2D plasma profile in Fig. 3c. (d) Energy-loss measurements for the same plasma versus the probing time, for argon projectile ions at a velocity ratio vp/≈3.111. The data are compared with the predictions of the LP and the TM stopping-power models applying a Monte-Carlo description as well as the Gus’kov and the Kreussler models for the effective projectile charge state. The energy loss is normalized to its value in the solid target (100%), as well as the plasma areal density (ρR). The error bars correspond to one s.d. (1σ) of the uncertainty in the time shifts of the signals obtained from the TOF measurements.