4,745 research outputs found
Two-dimensional model of intrinsic magnetic flux losses in helical flux compression generators
Helical Flux Compression Generators (HFCG) are used for generation of
mega-amper current and high magnetic fields. We propose the two dimensional
HFCG filament model based on the new description of the stator and armature
contact point. The model developed enables one to quantitatively describe the
intrinsic magnetic flux losses and predict the results of experiments with
various types of HFCGs. We present the effective resistance calculations based
on the non-linear magnetic diffusion effect describing HFCG performance under
the strong conductor heating by currents.Comment: 29 pages,18 figure
Simulation of an Axial Vircator
An algorithm of particle-in-cell simulations is described and tested to aid
further the actual design of simple vircators working on axially symmetric
modes. The methods of correction of the numerical solution, have been chosen
and jointly tested, allow the stable simulation of the fast nonlinear multiflow
dynamics of virtual cathode formation and evolution, as well as the fields
generated by the virtual cathode. The selected combination of the correction
methods can be straightforwardly generalized to the case of axially
nonsymmetric modes, while the parameters of these correction methods can be
widely used to improve an agreement between the simulation predictions and the
experimental data.Comment: 9 pages, 3 figure
To the positive miscut influence on the crystal collimation efficiency
The paper concerns the crystal based collimation suggested to upgrade the
Large Hadron Collider collimation system. The issue of collimation efficiency
dependence on the muscut angle characterizing nonparallelity of the channeling
planes and crystal surface is mainly addressed. It is shown for the first time
that even the preferable positive miscut could severely deteriorate the
channeling collimation efficiency in the crystal collimation UA9 experiment. We
demonstrate that the positive miscut influence can increase the nuclear
reaction rate in the perfectly aligned crystal collimator by a factor of 4.5.
We also discuss the possible miscut influence on the future LHC crystal
collimation system performance as well as suggest simple estimates for the beam
diffusion step, average impact parameter of particle collisions with the
collimator and angular divergence of the colliding particle beam portion.Comment: 14 pages, 9 figure
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