Equilibrium and Stability of a Three-Dimensional Toroidal MHD Configuration Near its Magnetic Axis

Abstract

M onodentate, Semicarbazone, Thiosem icarbazone, But-2-yne, Tungsten(II) Reaction of [W I(C O )(N C M e)(dppm )(772 -M eC2M e)][BF4] {dppm = Ph2 P(C H 2 )PPh2} with an equim olar quantity of L {L = R R 'C N N H C O N H 2 (R = R ' = Me; R = H, R ' = Ph)} or L {L = R R 'C N N H C S N H 2 (R = R ' = Me, Et; R = Me, R ' = E t, Pr", Bu', Ph; R = H, R ' = Ph)} gives the m onodentately coordinated sem icarbazone or thiosem icarbazone products [W I(CO)L(dppm)(?7 2 -M eC2M e)][BF4] (1 -9 ) . 13C N M R spectroscopy suggests that the but-2 -yne ligand is donating four electrons to the tungsten in [W I(CO){H(Ph)CNN H CSN H 2 }(dppm)(?7 2 -M eC2M e)][BF4].

Physics in the magnetic configuration space of W7-X

“…In a quite different region of the W7-X configuration space at low-ῑ a and very high b 01 > 0.2, a vacuum magnetic hill appears [27]. These configurations are predicted to be Mercier unstable similarly to the inward-shifted LHD configurations [14,28].…”

Stellarator and tokamak plasmas: a comparison

“…From an expansion of Maxwell's equations in the vicinity of the magnetic axis, the average number of poloidal turns of a field line in one toroidal revolution can be expressed as an integral along the length l once around the magnetic axis [4,5],…”

Magnetic well and Mercier stability of stellarators near the magnetic axis

“…Weights are chosen to combine multiple objectives into a single objective function, and one is left wondering whether a different choice of weights might lead to promising magnetic configurations in a different region of parameter space. An older approach for relating stellarator geometry to physics properties is to make an asymptotic expansion in large local aspect ratio (Mercier 1964; Solov'ev & Shafranov 1970; Mercier & Luc 1974; Lortz & Nührenberg 1976; Garren & Boozer 1991 b ). Such an expansion is accurate in the core of any stellarator, even those for which the aspect ratio of the boundary is low (Landreman 2019).…”