The Low-B plasma, equilibrium and stability in Heliotron magnetic field

Abstract

An equilibrium and stability problems of a plasma in lieliotron magnetic field are discussed under the assumption that the plasma behaves such as hydromagnetic fluid and its pressure is much less than a magnetic pressure.
When the plasma carries only a diamagnetic J_θ current and not a j_z current due to a external electric field, for instance, joule heating electric field, the plasma quantities satisfying the equilibrium conditions take some reasonable distribution.
Both equilibrium plasma pressure and diamagnetic current can be expressed respectively in the forms.
P=α₀ψ₀/n (1-ψ/ψ₀) ⁿj_θ=-α₀r (1-ψ/ψ₀) ^n-1where φ=rA_θ
The stability condition for the flute type instability is given as follows;γpB²∂/∂ψ (1/B²) +∂p/∂ψ>0.
The equilibrium state satisfying the above condition takes the next inequality;γ/n>1.51
where γ is the ratio of the specific heats.