Integrated probing of sheath field evolution using laser-generated positrons

Positrons generated by ultraintense lasers are rapidly accelerated by TNSA fields, and may offer an integrated, temporally resolved probe of these fields for multi-picosecond, kilojoule class lasers such as NIF ARC. The use of positron spectral information as a diagnostic of target conditions is evaluated using 2D LSP PIC simulations, which are compared with experimental results collected at OMEGA EP [1]. A capacitor model [2] is used to predict the charging of the target and the energies of the positron spectral features. The factors that influence the target fields over time and corresponding positron acceleration are discussed.

[1] Chen et al., PoP 22, 056705 (2015)

[2] Link et al., PoP 18, 053107 (2011)