Fusion Neutron and Soft X-Ray Generation in Laser Assisted Dense Plasma Focus
The Langmuir frequency of the dense plasma focus matches closely the CO2 laser frequency; consequently, a strong absorption is expected within the volume of contained plasma. For thermo-nuclear radiation effects studies, laser assisted plasma focus can be employed for fusion neutron or soft X-ray pulse generation. In the latter case, high-Z material is laser-injected into the nascent focus, and plasma cooling by enhanced X-ray radiation is compensated by laser heating. Laser to X-ray energy conversion efficiencies near 50% are feasible. Numerical calculations for ff, fb,bb and total radiation for 5% Cu or Fe injection into focus to enhance the X-ray yield are presented for electron temperatures from 0.5 to 10 keV. Contrary to the X-ray generation, estimates of increase in neutron yield depend upon model assumed for dense focus. Furthermore, at electron temperatures in excess of 1 keV, the critical electron density must be maintained and the anomalous absorption invoked to obtain the laser energy absorption in a single pass through focus. Estimates for the threshold of the anomalous absorption are presented. Most of the calculations were performed in the context of the single fluid boiler model, although estimates for the X-ray enhancement are model independent. The required laser energies of 102 to 103 J per 10−7 sec pulse are obtainable from a segmented cylindrical electron-beam preionized CO2 laser device.
KeywordsPlasma Focus Laser Heating Plasma Focus Device Fusion Neutron Dense Plasma Focus
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