相关论文: A novel non-adiabatic approach to transition cross…
Controlling non-linear effects in the transverse dynamics of charged particle beams in circular accelerators opens new possibilities for controlling some of the beam properties. Beam splitting by crossing a stable 1D non-linear resonance is…
A recent study [1] has introduced an advanced method aimed at extracting from a circular particle accelerator over millions of turns using stable islands and a bent crystal. This technique leverages the strength of non-linear beam dynamics…
Non-linear effects have become increasingly relevant in modern circular particle accelerators, and in recent years a change of paradigm has appeared, the attitude towards nonlinear effects having shifted from fighting them to exploiting…
New developments in accelerator physics have broadened the set of available techniques for manipulating charged-particle beams. Adiabatic trapping and transport of beam in resonance islands has been studied and successfully implemented at…
In an accelerator, the nonlinear behavior near a horizontal resonance line ($n\nu_x$) usually involves the appearance of stable fixed points (SFPs) in the horizontal phase space, also referred to as transverse resonance island ``buckets"…
In circular accelerators, crossing the linear coupling resonance induces the exchange of the transverse emittances, provided the process is adiabatic. This has been considered in some previous works, where the description of the phenomenon…
To understand the recently observed mysterious non-adiabatic energy transfer for hyperthermal H atom scattering from a semiconductor surface, Ge(111)c(2*8), we present a mixed quantum-classical non-adiabatic molecular dynamics model based…
The transition energy must be crossed in the CERN PS to accelerate proton and ion beams to flat-top energy. A phase jump of the accelerating RF voltage with respect to the phase of the bunches by about 180 degrees minus twice the…
Transitions in an artificial atom, driven non-adiabatically through an energy-level avoided crossing, can be controlled by carefully engineering the driving protocol. We have driven a superconducting persistent-current qubit with a…
We investigate the transition of a quantum wave-packet through a one-dimensional avoided crossing of molecular energy levels when the energy levels at the crossing point are tilted. Using superadiabatic representations, and an approximation…
In fast wave current drive, the resonant electron is accelerated by fast wave in the direction parallel to the static magnetic field, and the parallel velocity will be increased. The trajectories of the trapped resonant electrons are…
The concept of large-radius multistage coaxial cyclotrons having separated orbits is described, to generate proton beams of 120-2000 MeV energy at tens of GW pulsed and hundreds of MW in continuous beam power operation. Accelerated beam…
For typical perturbations of convex integrable Hamiltonian system with three degrees of freedom, a path of diffusion is established to cross strong double resonant point. Together with the uniform hyperbolicity of invariant cylinders got in…
The predominant source of nonlinearity in most existing accelerators are sextupoles, which introduce nonlinear resonances. When the horizontal tune of an accelerator is near such a resonance line ($n\nu_x$), stable fixed points (SFPs) may…
Electron cloud effects have become one of the main performance limitations for circular particle accelerators operating with positively-charged beams. Among other machines worldwide, the CERN Super Proton Synchrotron (SPS), as well as the…
Crossing a horizontal nonlinear resonance is the approach that can be used to split a beam in several beamlets with the goal to perform multi-turn extraction from a circular particle accelerator. Such an approach has been successfully…
We investigate the well-known Shin-Metiu model for an electronic crossing, using both a standard Born-Huang (BH) framework and a novel phase space (PS) electronic Hamiltonian framework. We show that as long as we are not in the strongly…
A charged particle in a magnetic field possesses discrete energy levels associated with particle's rotation around the field lines. The radiative transitions between these levels are the well-known cyclotron transitions. We show that a…
Recent simulations have shown that, even when the magnetic field of a stellarator possesses nested toroidal flux surfaces, the orbits of passing energetic particles can exhibit islands. These 'drift islands' arise near rational flux…
Based on a semi-empirical generalized Anderson-Newns model we construct a pseudo-particle description for electron emission due to de-excitation of metastable molecules at surfaces. The pseudo-particle approach allows us to treat resonant…