Energy confinement and MHD stability in BeltPinch IIa

In the Belt-Pinch IIa, toroidal plasmas with highly elongated cross-sections are produced by shock heating. This results in highβ plasmas with the shape: height approximately 200 cm, thickness approximately 20 cm, radius approximately 50 cm. Typical plasma parameters are T approximately 70 eV, nsub(emax) approximately 3.5x1014 cm-3 at Bsub(t)=1-2kG, Bsub(p)=0.3-0.7 kG, Isub(p) approximately 200 kA. The plasma beta decays in approximately 70 μs. With a radial compression ratio of 2.1, plasmas could be confined without obvious instabilities for the entire high-β phase, i.e. approximately 45 MHD growth times. With a higher compression ratio of 3.2, the plasma disintegrates into several filaments in about 10 μs. (author)