Plasma liner

Figure 12-8A. Piston rings. The piston rod is manufactured from heat-treated stainless steel and is coated with wear-resistant overlays, such as ceramic, chromium oxide, and tungsten carbide applied by plasma techniques. Piston rod cross-head attachment has mechanical preloading system for the threads. Rider rings and seal rings are manufactured from PTFE filled resins fillers are matched to the gas, piston speed, and liner specifications. Typical fillers are glass, carbon, coke, or ceramic. (Used by permission Bui. BCNA-3P100. Howden Process Compressors Incorporated. All rights reserved.)...

The crucial factor in the present formation scheme is the reconnection processes occurring near the liner surface. Various different values of plasma resistivity and anomalous resistivity [35] were also tested. It was found that the reconnection phenomenon is rather insensitive to electron temperature if is larger than 0,5 eV,... 

The immediate aim of the spheromak experiment is to study the qualitative behavior and plasma transport properties of a high temperature spheromak plasma. In order to carry out this goal/ it is necessary to increase the electron temperature high enough to minimize the ambiguity related to atomic/molecular processes and impurity radiation losses (T > 100 -200 eV). The choice of the metallic liner and equi-psi surface approach should also reduce the impurity migration from the core surface. 

One of the problems caused by the liner is substantial energy loss on its surface, since the L/R time constant of the thin liner is comparable to the plasma formation time constant. During the plasma formation, 85 kJ and 65 kJ are lost due to poloidal and toroidal liner currents, respectively. In the no-plasma mode or in the failure mode, the energy d imped on the liner is large. The joule loss in the plasma is expected to be 80 kJ with 0.5 eV starting electron temperature and classical resistivity. The final plasma has a stored magnetic energy of 50 kJ in both the poloidal and toroidal fields. 

The maximum flux which can be delivered from the capacitor banks is 1 5 volt sec and 0.1 volt sec of poloidal flux and toroidal flux, respectively. However, due to the large phase shift caused by the metallic liner the available flux to produce poloidal flux in the plasma is about 0.6 volt sec. In the toroidal direction most of the flux is delivered to the plasma, since L/R is relatively short. The captured flux in the final plasma is 0.2 volt sec and 0.05 volt sec in poloidal and toroidal direction. The q-value at the center is 0.38. 

Considering the state of the art in the 1950 s, this meant speeds of the order of 10 cm/sec and the only conductor capable of these speeds was plasma. Based on these ideas we designed and constructed an experiment shown in Fig. 2. The plasma piston is a plasma liner imploding into a cylindrical cavity, compressing a Tuo mode in the 5-band. 

Fig. 2 - Plasma liner implosion into cylindrical cavity.

Y) is the efficiency of energy-conversion from the source to the liner, JVpy Wm and Wl being the energy, of the internal plasma, the energy of the magnetic field and the liner energy, respectively. In a system without tamping this condition can be rewritten in the now more familiar form rp 0.3 g/cm. ... 

The experiment has supplied encouraging results on the acceleration of plasma liners and on the concentration of their energy in a small volume. In order that meaningful answers to the fusion problem can be obtained, it is necessary to scale up the apparatus, simplify the injection problem and as already mentioned, provide separate deuterium injection . 

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