Interesting (Sometimes Unique) Plasma Properties of Spherical Torus are Anticipated in NSTX
- Current startup via coaxial helicity injection or RF methods alone
- MHD-stable plasma at very high average toroidal beta (~40%) with well-aligned bootstrap current, strong magnetic shear, and deep magnetic well (~30%), in the presence of nearby conducting shell
- High stable beta (~25%) in the absence of conducting shell
- Very high flow shearing rate (by two orders of magnitude over tokamak) and magnetic shear (near edge), indicating a strong tendency to suppress plasma microinstabilities and enhance confinement (or introduce new instabilities?)
- Suppression of electrostatic and electromagnetic instabilities via reversal of orbit precession resulting from strong magnetic well
- Strong absorption of High Harmonic Fast Wave for plasma heating and current drive (for plasmas with large dielectric constant)
- Naturally diverted SOL in NSTX has large mirror ratio (~4-to-1) and flux expansion factor (³10), dispersing particle and heat fluxes
- Double-null divertor SOL has a 2-to-1 mirror ratio