scholarly journals Траекторный анализ в коллекторе с многоступенчатой рекуперацией энергии для прототипа гиротрона DEMO. Часть I. Идеализированное распределение магнитного поля

2021 ◽  
Vol 91 (1) ◽  
pp. 135
Author(s):  
О.И. Лукша ◽  
П.А. Трофимов ◽  
В.Н. Мануилов ◽  
М.Ю. Глявин
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Electric Fields ◽  
Beam Energy ◽  
Trajectory Analysis ◽  
Spatial Separation ◽  
Maximum Efficiency ◽  
Azimuthal Magnetic Field

The results of modeling of collector for the gyrotron prototype being developed for the DEMO project are presented. A trajectory analysis in a collector with a 4-stage recovery of the residual beam energy based on the method of spatial separation of electrons in crossed azimuthal magnetic and axial electric fields was performed. In this part of the study, the formation of the azimuthal magnetic field was carried out using a conductor located on the axis of the device. The study was performed for a spent electron beam with a velocity and coordinate distribution of particles close to those obtained in experiments with powerful gyrotrons. Due to a thorough choice of the geometry of the collector sections, a total gyrotron efficiency of more than 80% was achieved, which is close to maximum efficiency with perfect separation of fractions of an electron beam with different energies. The data obtained will be used for development of a toroidal solenoid designed to create an azimuthal magnetic field.

scholarly journals New possibilities of collectors with azimuthal magnetic field for multistage energy recovery in gyrotrons

2021 ◽  
Vol 2103 (1) ◽  
pp. 012058
Author(s):  
I Louksha ◽  
P A Trofimov ◽  
B D Usherenko
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Energy Recovery ◽  
Trajectory Analysis ◽  
Spatial Separation ◽  
Total Efficiency ◽  
Optimal Parameters ◽  
Azimuthal Magnetic Field ◽  
Electron Trajectories ◽  
Collector Region

Abstract The results of modeling a collector with 4-stage recovery of residual electron energy for the SPbPU gyrotron with a frequency of 74.2 GHz and an output power of 100 kW are presented. For spatial separation of electrons with different energies, an azimuthal magnetic field created by a toroidal solenoid is used. An increase of the recovery efficiency and a decrease of the current of electrons reflected from the collector is achieved by reducing the spread of the radial position of the leading centers of electron trajectories at optimal parameters of the toroidal solenoid, as well as by using a sectioned electron beam. The trajectory analysis of the spent electron beam in the collector region showed the possibility of achieving the total efficiency of the gyrotron, close to 80%.

scholarly journals Траекторный анализ в коллекторе с многоступенчатой рекуперацией энергии для прототипа гиротрона DEMO. Часть II. Тороидальное магнитное поле

2021 ◽  
Vol 91 (7) ◽  
pp. 1182
Author(s):  
О.И. Лукша ◽  
П.А. Трофимов ◽  
В.Н. Мануилов ◽  
М.Ю. Глявин
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Trajectory Analysis ◽  
Spatial Separation ◽  
Electron Velocity ◽  
Maximum Efficiency ◽  
Recovery Efficiency ◽  
Optimal Parameters ◽  
Electron Trajectories ◽  
Overall Efficiency

The results of modeling of a collector with four-stage recovery of the residual beam energy for the prototype gyrotron designed for the DEMO project are presented. For spatial separation of electrons with different energies, the azimuthal magnetic formed by a toroidal solenoid is used. An increase of the recovery efficiency and a decrease of the flow of electrons reflected from the collector are achieved by reducing the spread of radial position of the leading centers of electron trajectories at the optimal parameters of the toroidal solenoid, as well as by using a sectioned electron beam. Trajectory analysis of the spent beam with electron velocity and coordinate distributions close to those obtained in experiments with high-power gyrotrons showed the possibility of achieving an overall efficiency of the gyrotron higher than 80 %, which is close to the maximum efficiency at ideal separation of electron beam fractions with different energies.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

scholarly journals High-current electron beam nonlinear relaxation in plasma and electron acceleration

1988 ◽  
Vol 6 (3) ◽  
pp. 607-612
Author(s):  
D. M. Karfidov ◽  
N. A. Nikolov ◽  
P. N. Malinov ◽  
I. P. Trifonov
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Beam Energy ◽  
Modulation Instability ◽  
Plasma Waves ◽  
High Current ◽  
High Current Electron Beam ◽  
Nonlinear Relaxation ◽  
Current Electron ◽  
High Current Electron

A nonlinear relaxation is observed when an electron beam interacts with plasma in an external magnetic field. An acceleration of electrons to energies which are more than twice that of the initial beam energy is observed. The acceleration mechanism is connected with the modulation instability of the plasma waves which is excited when the beam relaxes.

Energy conversion by electron beam-driven waves in a compressed reconnection separatrix

2020 ◽  
Author(s):  
Justin Holmes ◽  
Rumi Nakamura ◽  
Owen Roberts ◽  
Daniel Schmid ◽  
Takuma Nakamura ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Energy Conversion ◽  
Electric Fields ◽  
Spatial Configuration ◽  
Three Dimensional ◽  
Lower Hybrid ◽  
Magnetic Compression ◽  
Rotational Discontinuity ◽  
Highly Correlated

<p>We investigate magnetic compression near the reconnection separatrix observed by Magnetospheric MultiScale (MMS) on July 11<sup>th</sup> 2017. A clear transition between inflow and outflow in both ions and electrons is observed across an ion gyro-scale region of enhanced magnetic field. Multispacecraft techniques for magnetic curvature and local gradients along with timing of highly-correlated wave packets are used to determine the spatial configuration of the compressed region. Structure of the system is found to be inherently three dimensional; electron beam-driven modes propagating parallel to the magnetic field are observed concurrent with perpendicular-propagating lower hybrid waves. Larger scale surface waves are also present behind the compression front. Transforming to a deHoffmann-Teller frame across the boundary results in a distinctly non-rotational discontinuity with structure similar to a quasi-2D, Petschek-like slow shock. However, MHD jump conditions are not satisfied, indicating kinetic dissipation may occur within the thin layer. The largest amplitude measurements of $\mathbf{J}\cdot\mathbf{E}$ energy conversion are associated with an inflowing electron beam and parallel electric fields near the magnetic peak. Spikes in $\mathbf{J}\cdot\mathbf{E}$ are predominantly negative, suggesting electron-scale mixing between the reconnection inflow and outflow is partially responsible for the observed magnetic compression.</p>

scholarly journals The method of an intense electron beam modulation

1994 ◽  
Vol 12 (4) ◽  
pp. 719-724 ◽  
Author(s):  
V.T. Astrelin ◽  
S.V. Lebedev
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Relativistic Electron ◽  
Computer Simulations ◽  
Relativistic Electron Beam ◽  
Azimuthal Magnetic Field ◽  
Beam Modulation ◽  
Intense Electron Beam ◽  
Beam Reflection ◽  
Intense Electron

A new method of intense relativistic electron beam modulation at frequencies up to ∼1 GHz is suggested. Current modulation is provided by using the azimuthal magnetic field of the beam to control the beam reflection from the magnetic mirror. The results of computer simulations for a 2-MeV, 20–50-kA beam are presented.

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