PRODUCTION OF A HIGH-DENSITY AND HIGH-TEMPERATURE PLASMA WITH AN INTENSE HIGH-CONTRAST SUBPICOSECOND LASER

We report on the observation of high-electron-density (n(e) almost-equal-to 15n(c) where n, is the critical density, 4 x 10(21) cm-3 for lambda = 0.53 mum) and high-temperature (T(e) almost-equal-to 400 eV) plasma obtained when an intense high-contrast 400-fs laser pulse interacts with a solid Al target. After the laser intensity is increased from 10(16) to 5 x 10(17) W/cm2, the kiloelectron-volt x-ray emission is brighter by approximately an order of magnitude and is still produced from very dense plasma (6 x 10(22) cm-3).