Heating of FRC plasma electron and improvement of confinement by intense pulsed ion beam

点击翻译按钮获取中文摘要

A theoretical and experimental investigation on FRC plasma transport revealed a confinement scaling of plasma particle and trapped magnetic flux which indicated that the transport mechanism of particle and trapped flux was classical and the decay time time of particle (tau_N) was f (alpha)・tau_c/{l+1.2x10^3・epsilon^<-2.7>}, where tau_c was a characteristic time of 1-D (radial) MHD classical the flux-decay (mu・r_s^2/4・eta_<cla.>, mu : permeability and eta_<cla.> : Spitzer's resistivity) and epsilon was a plasma aspect ratio (=l_s/2r_s, : r_s plasma radius and l_s : its length). The decay time of trapped flux (tau_<phi>) was alpha・tau_N and a value of f (alpha) was around 0.3 for alpha=1.Two methods were proposed in order to verify the scaling law. The first was the plasm formation of as high value of epsilon as possible to confirm its dependence on plasma geometry. The second was plasma electron heating to its basic feature of the classical transport by the axial injection of a magnetic … More ally insulated, electrode-geometrically focused, and pulsed intense ion beam of several ten NW (-50keV,-kA,and * 10mus), an ion diode of which had been under construction.During the term of this project, constructed was a plasma generation device with a pinch coil of 22cm in diameter and 150cm in length and with extenal field of 8kG at the maximum and of 1.6mus in rising, on the device of which formed might be an FRC plasma of r_s=9cm and l_s=100-120cm (epsilon=ll-14). Its value of tau_N corresponded to 0.37-0.48・f・tau_c (130-170mus for Te=100eV and alpha=1). The device was coming to operate soon.An efficiency of heating plasma by the axial injection of the 50keV proton was estimated numerically for the hydrogen plasma of a dimension shown above using a rather realistic profile of FRC,which was deduced from a 2-D pressure equilibrium calculation combined with the 1-D plasma transport simulation. The efficiency o heat the plasma inside the separatrix was 30% for Te=50eV and about 10% for Te=100eV.This value might be enough to the plasma significantly by the pulsed ion beam. Less