High-intensity electron linacs have severe space-charge effects that lead to the production of beam halo which degrade the beam quality. For a given charge per bunch, hollow beams have a weaker nonlinear space-charge force. In this paper, we have investigated the possibility of using hollow beam to control halo growth in linacs. We simulate the dynamics of such a beam in a 17 MeV radio frequency linac using ASTRA beam dynamics code and show that it experiences a smaller emittance growth as well as reduced beam halo. The results suggest that using a hollow beam, high charge per bunch could be propagated and accelerated in a radio frequency linac.

In light of the increased interest in e-mobility, comfortable, and safe charging systems, such as inductive charging systems, are gaining importance. Several standardization bodies develop guidelines and specifications for inductive power transfer systems in order to ensure a good interoperability between different coil architectures from the various car manufacturers, wireless power transfer suppliers, and infrastructure companies. A combination of a bipolar magnetic coil design on the primary side with a secondary solenoidal coil promises a good magnetic coupling and a high-transmitted power with small dimensions at the same time. In order to get a profound knowledge of the influence and behavior of the main variables on the coil system, a detailed parameter study is conducted in this paper. Based on these findings, a solenoid was designed for a specific case of application. Further, this design is optimized. The dimensions of the system could be reduced by 50% with a constant coupling factor at the same time. Besides the reduction of the dimensions and subsequently the costs of the systems, the stray field could be reduced significantly.

We prove that if f:I=[0,1]→I is a C3-map with negative Schwarzian derivative, nonflat critical points and without wild attractors, then exactly one of the following alternatives must occur: (i) R(f) has full Lebesgue measure λ; (ii) both S(f) and Scramb(f) have positive measure. Here R(f), S(f), and Scramb(f) respectively stand for the set of approximately periodic points of f, the set of sensitive points to the initial conditions of f, and the two-dimensional set of points (x,y) such that {x,y} is a scrambled set for f.Also, we show that if f is piecewise monotone and has no wandering intervals, then either λ(R(f))=1 or λ(S(f))>0, and provide examples of maps g,h of this type satisfying S(g)=S(h)=I such that, on the one hand, λ(R(g))=0and λ2 (Scramb (g))=0 , and, on the other hand, λ(R(h))=1 .