DocumentCode :
777377
Title :
Heating of on-axis plasma heating for keV X-ray production with Z-pinches
Author :
Chuvatin, Alexandre S. ; Rudakov, Leonid I. ; Velikovich, Alexander L. ; Davis, Jack ; Oreshkin, Vladimir I.
Author_Institution :
Lab. de Phys. et Technologie des Plasmas, Ecole Polytechnique, Palaiseau, France
Volume :
33
Issue :
2
fYear :
2005
fDate :
4/1/2005 12:00:00 AM
Firstpage :
739
Lastpage :
751
Abstract :
We discuss a new opportunity of using Z-pinch plasma radiation sources for generating Ar K-shell radiation and harder keV quanta. Our approach to keV X-ray generation is based upon an analogy with laser fusion, where the imploding shell compressionally heats the low-density inner mass. The suggested design of a Z-pinch load consists then of one or two heavy outer shell(s) with a lower mass on-axis fill (i.e., central gas jet) producing most of the radiation. The outer shell is not supposed to radiate and thus does not need to have high specific energy characterized by the large η parameter (Whitney et al., 1990). Thus, the heavy outer shell does not need to have a very large initial diameter for its implosion to be matched to the long-pulse current driver. Rather, we want to have a large amount of energy from the driver coupled to this shell by the moment when the shell collides with the low-density fill and eventually converts much of this energy to the thermal energy of the on-axis plasma. This configuration is investigated numerically in the framework of a one-dimensional radiation-magneto-hydrodynamics model for the case of Ar K-shell radiators. It is demonstrated that the Ar fill is heated in two stages. The first stage corresponds to the shock heating and thermal conduction in an initially low-density fill, and it allows preheating the fill while avoiding significant losses in soft radiation. The fill radiator is then compressed quasi-adiabatically and is heated-up to the temperature optimum for K-shell quanta generation. Diffusion of the driving magnetic field is shown to always suppress the conductive heat losses from the hot on-axis plasma to the cold outer shell. Absorption of the K-lines emitted near the axis in the surrounding plasma could be avoided by filling the outer shell with a different gas (like N-on-Ar), which allows a substantial increase in the observed keV X-ray radiation yields.
Keywords :
Z pinch; argon; explosions; plasma X-ray sources; plasma collision processes; plasma density; plasma heating; plasma jets; plasma magnetohydrodynamics; plasma transport processes; Ar; K-line absorption; K-shell quanta generation; K-shell radiation; X-ray production; X-ray radiation yields; Z-pinches; central gas jet; cold outer shell; conductive heat losses; current driver; driving magnetic field diffusion; laser fusion; low-density fill; low-density inner mass; on-axis plasma heating; one-dimensional radiation-magnetohydrodynamics model; plasma radiation sources; plasma thermal energy; quasiadiabatic compression; shell implosion; shock heating; soft radiation; thermal conduction; Argon; Fusion power generation; Gas lasers; Heating; Laser fusion; Plasma sources; Plasma temperature; Plasma x-ray sources; Production; X-ray lasers; K-shell radiation production; Z-pinch plasmas; magnetohydrodynamics; plasma radiation sources;
fLanguage :
English
Journal_Title :
Plasma Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0093-3813
Type :
jour
DOI :
10.1109/TPS.2005.845304
Filename :
1420615
Link To Document :
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