The Coaxial Slow Source: Parallel operation and the radiation barrier

The Coaxial Slow Source (CSS) has previously been reported to produce annular FRCs on a slow time scale and at low voltages. The authors report here preliminary results from 2 aspects of the ongoing CSS research. The first is experimental results from the CSS operated in the parallel mode, CSS-P. The second topic involves analytical work on ohmic heating of a high <β> plasma with and without impurity radiation losses. The CSS has been modified to operate in the parallel mode. To accomplish this the outer single turn theta pinch coil has been modified to have four turns, the same as the inner coil. The coils are wired in parallel to the same capacitor bank so that the space between them is a flux conserver if the external inductance is negligible. Thus the total flux in the annulus between the two coils must always remain zero. If an additional flux conserving ring (plasma) is created between these coils, equal and opposite fluxes will build up on either side of it when the circuit is energized. This results in the plasma being centered between the coils without the radial dynamics associated with formation in the independent coil mode. The CSS-P can be operated in two different regimes. In the first the capacitor bank is energized before forming the plasma. In the second mode of operation, the plasma is produced before the coils are energized and involves only tearing formation