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Description
A plasma mirror reflected pulse was evaluated for staging applications. The Gemini north beam was focused just after a Kapton tape. On-tape intensities of $10^{19}-10^{21} Wm^{−2}$ generated a plasma mirror. The reflected pulse was used to drive a injection and acceleration in a gas cell.
The plasma mirror was operated with a reflectivity exceeding 70%, this fell for on-tape intensities nearing $3×10^{21} Wm^{−2}$. Reducing the spot area on the tape improved the reflected spot quality, increasing energy in FWHM for comparative intensities. These results are indicative of some pre-plasma formation and surface distortion. The plasma mirror reflected spot was used to drive an accelerator stage to ionisation injection. Ionisation injection was demonstrated with spots containing up to 0.4 ± 0.1 J in their FWHM at densities exceeding $2.7 ± 0.4 × 10^{24} m^{−3}$. Electrons were accelerated in a cell of $6.7 ± 0.8 × 10^{24} m^{−3}$ to energies up to 455 ± 28 MeV. At densities between $0.5 × 10^{24} m^{−3}$ and $2 × 10^{24} m^{−3}$, closer to ideal staging regimes, guiding and complete blue-shifting of the transmitted spot was observed.
These results inform our understanding of plasma mirrors operated at high intensity and indicate their utility for staging applications.
