Origin of the resistivity anomalies of (EDT–TTF)[M(dmit)₂](M = Ni, Pd)

Comparison between stellarator and tokamak divertor transport

“…The simulation results have shown the existence of a friction-dominated impurity transport regime at high SOL collisionalities for all these devices [27,[50][51][52]. Figure 13 shows how impurity density profiles throughout the stochastic layer in the LHD helical divertor change from peaked to hollow with increasing plasma separatrix density.…”

Stellarator and tokamak plasmas: a comparison

“…Coulomb collisions between heavy impurity ions (Z) and bulk plasma ions (i) lead to two forces on the former: a friction force proportional to the velocity difference V i − V Z , which tends to flush the impurities toward the target, and a thermal force proportional to the bulk-ion temperature gradient ∇ T i , which drives the impurities toward the hot core plasma. In tokamaks, the latter force tends to be stronger, but in stellarators numerical modelling suggests that a friction-dominated regime is accessible in LHD as well as in W7-AS and W7-X [75].…”

Unconventional charge ordering in Na0.70CoO2 below 300K?

“…In analogy with the high-T c cuprates it was argued that cobalt-oxide layers may result in unusual physical properties of these compounds, including unconventional superconductivity [1]. Indeed, recent experiments [2] suggest that the hydration of nominal Na 0.70 CoO 2 induces superconductivity below a critical temperature T c ≈ 5 K. Other recent investigations confirm that the physical properties of Na x CoO 2 are quite puzzling [3,4,5,6,7,8,9,10]. Na x CoO 2 , with x < 1, crystallizes in a hexagonal structure with P 6 3 /mmc space group symmetry [11,12], a structure consisting of Na layers, intercalated between sheets formed by triangular arrangements of CoO 6 octahedra.…”