Vortex Structures and Electron Beam Dynamics in Magnetized Plasma

We investigate the formation of vortex structures at the refl ection of an electron beam from the double layer of the Jupiter ionosphere. The infl uence of these vortex structures on the formation of dense upward electron fl uxes accelerated by the double layer potential along the Io flux tube is studied. The phase transition to the cyclotron superradiance mode becomes possible for these electrons. The conditions of the formation of vortex perturbations are considered. The nonlinear equation that describes the vortex dynamics of electrons is constructed, and its consequences are studied.

Accurate and confident prediction of electron beam longitudinal properties using spectral virtual diagnostics

Longitudinal phase space (LPS) provides a critical information about electron beam dynamics for various scientific applications. For example, it can give insight into the high-brightness X-ray radiation from a free electron laser. Existing diagnostics are invasive, and often times cannot operate at the required resolution. In this work we present a machine learning-based Virtual Diagnostic (VD) tool to accurately predict the LPS for every shot using spectral information collected non-destructively from the radiation of relativistic electron beam. We demonstrate the tool’s accuracy for three different case studies with experimental or simulated data. For each case, we introduce a method to increase the confidence in the VD tool. We anticipate that spectral VD would improve the setup and understanding of experimental configurations at DOE’s user facilities as well as data sorting and analysis. The spectral VD can provide confident knowledge of the longitudinal bunch properties at the next generation of high-repetition rate linear accelerators while reducing the load on data storage, readout and streaming requirements.

PIC-моделирование генерации CВЧ-излучения в отражательном триоде радиального типа с расходящимся замагниченным электронным пучком

This paper presents particle-in-cell simulation of the reflex triode with radially diverging magnetized electron beam. Dynamics of the electron beam and generation characteristics of the reflex triode are studied in the work. It is shown that two virtual cathodes are formed in it. It was calculated that the peak power of the microwave radiation reaches P=19 MW at the beam current I0=5 kA and potential of the cathode Uc=‒100 kV. There is a peak in the microwave radiation spectrum at the frequency ν = 5.2 GHz.

ELECTRON BEAM DYNAMICS AT OUTPUT MAGNETRON GUN IN GRADIENT MAGNETIC FIELD

The results of numerical calculations based on the electron beam dynamics generated by a magnetron gun in the transport channel in a gradient magnetic field are presented. The dependence of the final transverse distribution on a target on the amplitude and gradient of the magnetic field was investigated. The possibility of controlling the transverse dimensions of the beam has been studied. It was found that the electron flux undergoes radial compression, the magnitude of which is determined by the form of the gradient magnetic field. The main dependences of the electron beam motion in a given magnetic field are modeled. The possibility of adjusting the beam diameter by varying the magnetic field is shown.