Ultrahigh-speed plasma sources and liner compression of high-temperature plasma

The Open Fire series of multi-megampere experiments\footnote{P.J. Turchi, et al, ``Generation of High Energy X-Radiation Using a Plasma Flow Switch,'' JAP 69 (4), 1999.} on the Shiva Star capacitor bank achieved a megajoule of aluminum and (separately) tungsten ions at flow speeds in excess of 2000 km/s, corresponding to ion energies of 0.54 and 3.7 MeV, respectively. For the same kinematics, and pulser operation, the total flow energy would remain a MJ and the average ion energy for a DT plasma (at 2.5 AMU) would be 50 keV. These values suggest the possibility of ``isothermal'' compression by liner implosion to interesting particle densities at fusion-level temperatures. Based on the Open Fire experiments, the initial plasma density would be 10$^{17}$ cm$^{-3}$ in a volume of 1500 cm$^{3}$ at a temperature of 16 keV (after sharing energy with electrons). A 3-D liner implosion of about 5 MJ could isothermally compress this plasma to 10$^{20}$ cm$^{-3}$, with a dwell time at high density of about a microsecond, providing an n$\tau $-product of 10$^{14}$ s/cm$^{3}$. Such experiments, in which heat-loss actually helps, are within range of present systems, e.g., Shiva Star and Atlas.