Implosions of NaF plasmas for photopumping a Na-Ne x-ray laser

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.347569· OSTI ID:5552556

Young, F C; Hinshelwood, D D; Apruzese, J P ^[1]; Deeney, C; Nash, T; Prasad, R R ^[2]

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1. Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375-5000 (USA)
2. Physics International Co. San Leandro, California 94577 (USA)

Intense heliumlike sodium 11-A line radiation is required to resonantly photopump a neon plasma in the Na-Ne soft x-ray laser scheme. The implosion of a NaF capillary-discharge plasma with a 3-MA peak current is used to produce a power exceeding 100 GW in this He{alpha} line. The power is optimized by varying both the initial radius of the 3-cm-long NaF plasma column and the time delay between the capillary current and the generator current. Maximum power of 115 GW is obtained for implosions which occur just after peak current. Burn-through of the heliumlike sodium stage is evident in spectroscopic measurements where sodium Ly{alpha} line emission is 2--4 times stronger than He{alpha} emission. Mass loadings of 200--400 {mu}g/cm are inferred from measured implosion times and initial plasma diameters. The nearly pure density dependence of the He{alpha} power and the nearly pure temperature dependence of the Ly{alpha}/He{alpha} ratio allow the state of the plasma to be determined by measuring both quantities on a single shot. For these implosions, electron temperatures are 350--560 eV and total ion densities approach 10{sup 20} cm{sup {minus}3}. The mass load inferred from implosion dynamics is consistent with the ion density deduced from spectral measurements.

• OSTI ID: 5552556
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:11; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
ALKALI METAL COMPOUNDS
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ELEMENTS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
IMPLOSIONS
LASER IMPLOSIONS
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METALS
NEON
NONMETALS
OPTICAL PUMPING
PUMPING
RARE GASES
SODIUM
SODIUM COMPOUNDS
SODIUM FLUORIDES
X-RAY LASERS