Production of cold highly-ionized plasmas by intense subpicosecond lasers
Recent advances in high-intensity ultrashort-pulse lasers has made feasible the implementation of the transient recombination scheme for producing x-ray lasing in optical-field-ionized plasmas. This scheme involves plasmas consisting of fully stripped ions (or helium-like ions) and cold electrons. Immediately after the pump laser pulse, inversion occurs in hydrogen-like ions (or lithium-like ions) during the initial cascade of population through the excited levels of the ion. The gain duration is of the order of the radiative lifetime of the lasing transition, which is short compared with the recombination time. The major advantage of this approach is the ability to access very short wavelength resonance lines with high efficiency at achievable pump intensities. Moreover, this approach provides an ideal way of preparing the target medium for producing gain later in time on the type of transitions encountered in traditional rapidly cooled recombination lasers. There are two conditions that must be satisfied in order to produce gain using ultrashort-pulse lasers. The first condition is that the target media must be ionized to the fully stripped state (or to the helium-like state to implement lithium-like recombination schemes). The second condition is the residual electron energy produced immediately after the pump laser pulse must be low enough so that the system is far from ionization equilibrium and strong three-body recombination commences immediately. The first purpose of this paper is to show the laser intensity requirements for producing optical-field-ionized plasmas which are of interest to x-ray lasing. The second purpose of this paper is to show what residual electron energies will be produced at the minimum required pump laser intensities. 9 refs., 3 figs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5936761
- Report Number(s):
- UCRL-JC-106472; CONF-910711-5; ON: DE91010461
- Resource Relation:
- Conference: 20. international conference on phenomena in ionized gases, Barga (Italy), 8-12 Jul 1991
- Country of Publication:
- United States
- Language:
- English
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