A Toroidal Screw Pinch with Non-Circular Plasma Cross-Section

Application of MHD-theory to a screw pinch or Tokamak with circular cross-section shows that equilibrium and stability are obtainable only at β-values of the order of several per cent. Simple equilibrium and stability considerations for a screw pinch with flat plasma cross-section, however, showed that in this case β-values in the region β ≈ 1 should be allowed. Using the low inductive capacitor bank ISAR-IV, in a toroidal discharge chamber with a volume of 220 litres in flat geometry (50 cm mean diameter, 100 cm height) the plasma is produced by a fast rising magnetic field (rise time 6 μs, e-folding time ≈ 1 ms, peak field 10 kG). The results concerning equilibrium and stability of this flat plasma in the temperature regime of 100-200 eV are reported. (author)