Spectra from plasma created by very high intensity picosecond laser

Abstract

The Powerful Picosecond Laser (PP-Laser) System with an output power level of 20–30 GW and focused power density of 10 16 W/cm 2 has been operating as a part of the X-ray laser program at Princeton University for more than 2 yr (presently the PP-Laser System is producing power density which is larger by almost two orders of magnitude). Such a laser system creates an electric field which is greater than the Coulomb field in atoms. This may lead to a number of new physical processes like multiphoton excitation and ionization in a very strong field. Several spectra from the plasma created by the PP-Laser interacting with different solid targets are presented. Spectra were obtained in the range of 6–300 Å using the high resolution NRL-G SFC 3m XUV spectrograph. Very large broadenings of the lines from highly ionized ions were observed. Also presented are spectra recorded in a longer spectral range (up to visible), and some of the spectral line anomalies are discussed.