Demonstration designs for optical-field-ionized plasma x-ray lasers

Conference · Mon Feb 01 04:00:00 EST 1993

OSTI ID:6577251

Amendt, P A; Eder, D C; London, R A; Penetrante, B M; Rosen, M D

Previous studies of recombination x-ray lasers based on optical-field-induced ionization have stressed the conditions necessary for high gain and high output energy efficiency in Li-like Neon. Unfortunately, the higher electron density n[sub e] necessary to realize efficient generation of 98.26 [Angstrom] x rays in Li-like Neon also demands serious consideration of ionization-induced refractive defocussing. We propose a demonstration experiment of optical-field-ionized plasma x-ray lasing at 247[Angstrom] in Nitrogen which can tolerate strong refractive defocussing. The relatively low ionization potential energy of [approx]98 eV in Nitrogen should result in correspondingly low residual electron temperature T[sub e] which, in turn, allows large gain at lower values of electron density. The use of low electron density provides less collisional heating as well as reduced refractive defocussing. In addition to using low electron density to mitigate refraction, we also propose the use of a wide UV laser-driver focus to give reduced transverse intensity gradients near the laser axis. Milder transverse intensity gradients lead to longer refraction lengths which effectively define the volume of x-ray lasing. These two techniques for avoiding excessive refraction are used in tandem to identify an experimental regime where x-ray lasing dominates spontaneous noise by an unambiguous margin associated with a gain-length product of five. Such a margin is predicted to be exceeded for a Li-likeNitrogen plasma with n[sub e] [approx] 5[center dot]10[sup 19]cm[sup [minus]3], T[sub e] [approx] 10 eV, and a UV laser-driver intensity of 3[center dot]10[sup 16]W/cm[sup 2] with 0.25 [mu]m wavelength and 30 [mu]m waist radius.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6577251
• Report Number(s): UCRL-JC-112924; CONF-930159--24; ON: DE93009227
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
DESIGN
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELEMENTS
IONIZATION
LASERS
NITROGEN
NONMETALS
RECOMBINATION
X-RAY LASERS