Photoionized plasmas in laboratory: a connection to astrophysics and planetary sciences

摘要

In this work photoionized plasmas were created by irradiation of atomic and molecular gases by soft X-ray and extreme ultraviolet intense radiation pulses. Two different laser-produced plasma sources, employing a low energy Nd:YAG laser system (NL 129) and a high energy iodine laser system (PALS), were used for creation of photoionized plasmas. In both cases the SXR/EUV beam irradiated the gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Radiation spectra, measured for photoionized plasmas produced in Ne and Ar gases, are dominated by L-shell emission lines except the Ne plasma produced using the high energy system where K-shell emission dominates. Additionally electron density measurements were performed by laser interferometry employing a femtosecond laser system synchronized with the irradiating system. Maximum electron density for Ne plasma, induced using the high energy system, reached 2·10~(18)cm~(-3). In case of employing the low energy system a detection limit was too high for interferometric measurements, thus only an upper estimation for electron density could be made.