Figure 1

(a) Schematic of the experiment arrangement in which a Thomson spectrometer is used as an ion pinhole camera. (b) Optical scanned image of pits in CR-39 produced by fast uncharged atoms (recombined ions). Ions are accelerated from a central spot and from linear regions corresponding to the target edge. (c) Spatial mapping of pit distributions on a CR-39 detector in the dispersion plane of a Thomson spectrometer, produced using an automated scanning microscope with pit recognition software [20]. Mainly carbon ions are detected in distinct ion traces. (d) Enlarged region corresponding to fast neutral atoms undeflected in the spectrometer fields. Source regions are observed at the center of the target foil, A, at the edge of a $50\mu \mathrm{m}$ hole, B, and at the edges of the foil, C and D. (e) Enlarged region showing multiple carbon ion tracks. Each track results from one of the four source regions in (d).Reuse & Permissions

Figure 2

(a) Electron density $n$ 0.25 ps after the start of the laser pulse. The target profile ($400\mu \mathrm{m}$ radius and $10\mu \mathrm{m}$ thickness) is illustrated by the white line. The simulation space is cylindrically symmetric about the laser axis, marked by the (red) arrow. (b) Resultant $E$-field strength after 0.25 ps. (c),(d) Corresponding results 2.5 ps after the start of the laser pulse. (e) Temporal evolution of the potential drop over $25\mu \mathrm{m}$ from the surface of the target at given radii from the laser focal spot. The field becomes higher and remains high at the edge of the target ($400\mu \mathrm{m}$) for much longer than at smaller radii. A second later peak in the transient field at the smaller radii is produced by electrons which are reflected from the target edge and transverse the target again, in the opposite direction.Reuse & Permissions