132 research outputs found
Superselection in the presence of constraints
For systems which contain both superselection structure and constraints, we
study compatibility between constraining and superselection. Specifically, we
start with a generalisation of Doplicher-Roberts superselection theory to the
case of nontrivial centre, and a set of Dirac quantum constraints and find
conditions under which the superselection structures will survive constraining
in some form. This involves an analysis of the restriction and factorisation of
superselection structures. We develop an example for this theory, modelled on
interacting QED.Comment: Latex, 38 page
Gyrokinetic studies of the effect of beta on drift-wave stability in NCSX
The gyrokinetic turbulence code GS2 was used to investigate the effects of
plasma beta on linear, collisionless ion temperature gradient (ITG) modes and
trapped electron modes (TEM) in National Compact Stellarator Experiment (NCSX)
geometry. Plasma beta affects stability in two ways: through the equilibrium
and through magnetic fluctuations. The first was studied here by comparing ITG
and TEM stability in two NCSX equilibria of differing beta values, revealing
that the high beta equilibrium was marginally more stable than the low beta
equilibrium in the adiabatic-electron ITG mode case. However, the high beta
case had a lower kinetic-electron ITG mode critical gradient. Electrostatic and
electromagnetic ITG and TEM mode growth rate dependencies on temperature
gradient and density gradient were qualitatively similar. The second beta
effect is demonstrated via electromagnetic ITG growth rates' dependency on
GS2's beta input parameter. A linear benchmark with gyrokinetic codes GENE and
GKV-X is also presented.Comment: Submitted to Physics of Plasmas. 9 pages, 27 figure
Polarographische Untersuchungen zur automatischen Bestimmung des Urans in Kernbrennstoffloesungen
¹H- und ³¹P-KMR-Untersuchungen der Extraktionseigenschaften von Organophosphorverbindungen. I. Das System Tributylphosphat-Dodekan-HNO₃-H₂O
Simulating Gyrokinetic Microinstabilities in Stellarator Geometry with GS2
The nonlinear gyrokinetic code GS2 has been extended to treat
non-axisymmetric stellarator geometry. Electromagnetic perturbations and
multiple trapped particle regions are allowed. Here, linear, collisionless,
electrostatic simulations of the quasi-axisymmetric, three-field period
National Compact Stellarator Experiment (NCSX) design QAS3-C82 have been
successfully benchmarked against the eigenvalue code FULL. Quantitatively, the
linear stability calculations of GS2 and FULL agree to within ~10%.Comment: Submitted to Physics of Plasmas. 9 pages, 14 figure
Regelung eines Verdampfers zur kontinuierlichen Aufkonzentrierung von U-, Th- und Pu-Loesungen
¹H- und ³¹P-KMR-Untersuchungen der Extraktionseigenschaften von Organophosphorverbindungen. II. Das System Tributylphosphat-Dodekan- Uranylnitrat-HNO₃-H₂O
Zur maschinellen Auswertung von in-line Messgroessen bei der Wiederaufarbeitung bestrahlter Kernbrennstoffe
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