4,241 research outputs found
Nonaxisymmetric, multi-region relaxed magnetohydrodynamic equilibrium solutions
We describe a magnetohydrodynamic (MHD) constrained energy functional for
equilibrium calculations that combines the topological constraints of ideal MHD
with elements of Taylor relaxation.
Extremizing states allow for partially chaotic magnetic fields and
non-trivial pressure profiles supported by a discrete set of ideal interfaces
with irrational rotational transforms.
Numerical solutions are computed using the Stepped Pressure Equilibrium Code,
SPEC, and benchmarks and convergence calculations are presented.Comment: Submitted to Plasma Physics and Controlled Fusion for publication
with a cluster of papers associated with workshop: Stability and Nonlinear
Dynamics of Plasmas, October 31, 2009 Atlanta, GA on occasion of 65th
birthday of R.L. Dewar. V2 is revised for referee
A SCF MO Treatment of Some Tropone Derivatives
Recent work in these laboratories has led to the development of a semiempirical SCF MO treatm ent which seems to give extremely good results for ground States of conjugated molecules of ali kinds composed of carbon, hydrogen, nitrogen and oxygen. We have now applied this treatm ent to a problem of current
interest, namely the structures of tropolone and tropone deri
vatives. The calculations lead to the conclusion that neither of
these ring systems is in itself aromatic, while tropone is now re-
cognized to be polyenoid, tropolone still seems to be generally
regarded as aromatic. This belief, however, arose from the behavior
of tropolone derivatives in strong acid solution, where they exist
as hydroxy tropylium derivatives, or in alkali where they form
mesomeric anions. Calculated heats of formation, resonance ener-
gies, and bond lengths are reporte
- …