scholarly journals LONGITUDINAL TRAP OF ELECTRON BEAM IN POTENTIAL PIT MAGNETIC SOLENOIDAL FIELD

2021 ◽  
pp. 62-66
Author(s):  
Oleksandr Mazmanishvili ◽  
Nikolay Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Electron Beam ◽  
Electron Flow ◽  
Three Dimensional ◽  
Hamiltonian Formalism ◽  
Polar Angle ◽  
Longitudinal Motion ◽  
Gradient Magnetic Field ◽  
The Magnetic Field

A two-mode cylindrical magnetic field is considered, the potential of which has a minimum. The object of this work is the study of the parameters of an electron beam when it moves in a solenoid field with the longitudinal trap formed by the magnetic field, and the construction of the computational model of the motion of an electron beam. The problem is posed of the stability of the motion of electrons in such solenoid magnetic field. The possibility of obtaining oscillatory modes of particle motion has been studied. It was found that for oscillations of particles with an energy of tens of kiloelectronvolts in the potential well in a well, the field with the amplitude of tens of thousands of Oersteds is required. For the solenoid magnetic field of the solenoid, the formation of electron beam with an energy of 55 keV in the longitudinal and radial directions during its transportation is studied. A section of a magnetron gun was used as the physical object. One possible direction is to combine the two matched magnetic systems of the gun to create the potential magnetic field well. It is shown that, for the chosen conditions, the motion of electrons can be associated with the model of three-dimensional oscillations. In this work, on the basis of the Hamiltonian formalism of the motion of electrons in a magnetic field and an algorithm for numerically finding solutions to the differential equations of dynamics, a software tool is constructed that allows one to obtain arrays of values of particle trajectories in the volume. The use of the software made it possible to simulate the main dependences of the motion of the electron beam in a given two-mode solenoid magnetic field. The results of numerical simulation of electron trajectories in the gradient magnetic field with the point secondary emission cathode located in the middle of the system are presented. The formation of the beam with energy of 55 keV in the radial and longitudinal directions during its transportation in a solenoid magnetic field with a large gradient is considered. For significant time intervals, the possibility of three-dimensional oscillations is shown and the operating modes of the magnetic system are obtained, in which the particle undergoes stable three-dimensional oscillations. The influence of the initial conditions during emission on the occurrence of the reciprocating oscillatory effect has been studied. It is shown that for a given electron energy and fixed magnetic field, the parameter that determines the reflection of a particle, is the polar angle of entry relative to the axis of the cylindrical magnetic field. The dependence of the formation of the final distribution of particles on the amplitude and gradient of the magnetic field along the axis of the system is investigated. The results of numerical simulation on the motion of the electron flow are presented. The characteristics of the resulting electron beam are considered on the basis of a model of electron flow motion. The obtained simulation results show that it is possible to establish the phenomenon of oscillatory-return longitudinal motion under experimental conditions. Keywords: electron beam, magnetron gun, three-dimensional oscillations, electron dynamics, gradient magnetic field, mathematical modeling.

scholarly journals MODELING OF OSCILLATORY AND ROTARY TRAJECTORIES OF ELECTRONS IN GRADIENT MAGNETIC FIELD MAGNETRON GUN

2021 ◽  
pp. 117-120
Author(s):  
A.S. Mazmanishvili ◽  
N.G. Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Electron Flow ◽  
Polar Angle ◽  
Longitudinal Direction ◽  
Cathode Region ◽  
Gradient Magnetic Field ◽  
Bottleneck Effect ◽  
Large Gradient ◽  
Dynamics Of Particles

The motion of electrons in cylindrical magnetic field with variable strength along the axis is considered. The formation of a beam with energy of 55 keV in the longitudinal direction during its transport in solenoidal magnetic field with large gradient has been studied. The bifurcation regimes of the dynamics of particles during their move-ment along the transport axis both forward to the target and back to the cathode region are considered. The operat-ing modes of the gun are obtained, in which the particle experiences the "bottleneck" effect and returns to the cath-ode region. It is shown that for given electron energy and fixed magnetic field, the parameter that determines the reflection of the particle is the polar angle of entry with respect to the axis of the cylindrical magnetic field. The re-sults of numerical simulation on the motion of the electron flow are presented.

scholarly journals MULTI-PURPOSE MODES OF FORMATION OF ELECTRON BEAMS IN THE CYLINDRICAL MAGNETIC FIELD OF THE MAGNETRON GUN

2021 ◽  
pp. 45-49
Author(s):  
A.S. Mazmanishvili ◽  
N.G. Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electron Beam ◽  
Electron Beams ◽  
Electron Flow ◽  
Axial Direction ◽  
Beam Diameter ◽  
Transport Channel ◽  
Comparison Of The Results ◽  
The Magnetic Field

The results of the study on the formation of electron beams by the magnetron gun at various configurations of the magnetic field in the beam transport channel are presented. A technique for modeling the processes of formation of electron flows and control of the distribution of beams by collimation is presented. Numerical simulation of the dynamics of electron beams in the magnetic field of the gun for its various configurations has been carried out. Experimental data on the transportation and collimation of electron beams are presented. The possibility of stable formation of an electron beam in the axial direction during its transportation is shown. Imprints of the collimated electron beam were obtained on metal targets. The possibility of controlling the beam diameter by varying the magnetic field is shown. Comparison of the results of numerical modeling and experimental data on the motion and collimation of the tubular electron flow is carried out.

scholarly journals DYNAMICS OF AN ELECTRON BEAM FORMED BY MAGNETRON GUN WITH THE SECONDARY EMISSION CATHODE IN THE DECLINING MAGNETIC FIELD OF SOLENOID: EXPERIMENT AND SIMULATION

2021 ◽  
pp. 27-34
Author(s):  
Oleksandr Mazmanishvili ◽  
Nikolay Reshetnyak ◽  
Ganna Sydorenko
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Permanent Magnets ◽  
Initial Conditions ◽  
Electron Flow ◽  
Beam Current ◽  
Secondary Emission ◽  
Stray Field ◽  
The Magnetic Field ◽  
Emission Cathode

The article presents the results of research and calculations on the formation of a radial electron beam by a magnetron gun with a secondary emission cathode in the electron energy range 35...65 keV and measuring its parameters during transportation in the total decreasing magnetic field of thesolenoid and the stray field of permanent magnets. The beam was transported in a system consisting of copper rings with an inner diameter of 66 mm,located at a distance of 85 mm from the exit of the magnetron gun. The dependence of the beam current on the amplitude and gradient of the fielddecay has been studied. The studies carried out have shown the possibility of stable formation of a radial electron beam with an energy of tens of keVin the decreasing magnetic field of the solenoid. By optimizing the distribution of the magnetic field (created by the solenoid and ring magnets) and itsdecay gradient, it is possible to achieve an increase in the incident of electrons on one ring (up to ~72% of the beam current). On the basis of themathematical model of the movement of the electron flow, a software tool has been synthesized that makes it possible to obtain and interpret thecharacteristics of the resulting flows. The obtained numerical dependences are in satisfactory agreement with the experimental results for a magneticfield with a large decay gradient. Various configurations of the magnetic field are considered. Solutions to the direct problem of modeling electrontrajectories for given initial conditions and parameters are obtained. Various configurations of the magnetic field are considered. It is shown that forthe selected initial conditions for the electron beam and the distributions of the longitudinal magnetic field along the axis of the gun and the transportchannel, the electron flux falls on a vertical section, the length of which is on the order of a millimeter. Thus, by changing the amplitude anddistribution of the magnetic field, it is possible to control the current in the radial direction along the length of the pipe, and, therefore, the place of theelectron irradiation.

scholarly journals Condition for magnetic insulation of the electron beam in a rod-pinch diode

2003 ◽  
Vol 21 (2) ◽  
pp. 273-277 ◽  
Author(s):  
A.V. KIRIKOV ◽  
S.YA. BELOMYTTSEV ◽  
V.V. RYZHOV ◽  
I.YU. TURCHANOVSKY ◽  
V.P. TARAKANOV
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
High Speed ◽  
Electron Flow ◽  
Naval Research ◽  
High Current ◽  
Magnetic Insulation ◽  
Momentum Fluxes ◽  
The Magnetic Field ◽  
Theoretical Results

A condition for the transition of the electron beam produced in a coaxial rod-pinch diode to the mode of magnetic insulation has been established from the law of conservation of particle and field momentum fluxes. The magnetic field of the external current has been shown to contribute twice as much to magnetic insulation of the beam as the magnetic field of the electron beam self-current. Based on the relations derived, a model has been constructed for magnetic insulation of the electron flow in high-current rod-pinch diodes, which are used for radiography of high speed phenomena. The obtained theoretical results agree well with the results of numerical calculations and with experimental data gained at the Naval Research Laboratory (USA).

Three-dimensional MHD flows in rectangular ducts with internal obstacles

2000 ◽  
Vol 418 ◽  
pp. 265-295 ◽  
Author(s):  
B. MÜCK ◽  
C. GÜNTHER ◽  
U. MÜLLER ◽  
L. BÜHLER
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Magnetic Fields ◽  
Interaction Parameter ◽  
Hartmann Number ◽  
Three Dimensional ◽  
Side Length ◽  
Two Dimensional ◽  
The Magnetic Field

This paper presents a numerical simulation of the magnetohydrodynamic (MHD) liquid metal flow around a square cylinder placed in a rectangular duct. In the hydrodynamic case, for a certain parameter range the well-known Kármán vortex street with three-dimensional flow patterns is observed, similar to the flow around a circular cylinder. In this study a uniform magnetic field aligned with the cylinder is applied and its influence on the formation and downstream transport of vortices is investigated. The relevant key parameters for the MHD flow are the Hartmann number M, the interaction parameter N and the hydrodynamic Reynolds number, all based on the side length of the cylinder. The Hartmann number M was varied in the range 0 [les ] M [les ] 85 and the interaction parameter N in the range 0 [les ] N [les ] 36. Results are presented for two fixed Reynolds numbers Re = 200 and Re = 250. The magnetic Reynolds number is assumed to be very small. The results of the numerical simulation are compared with known experimental and theoretical results. The hydrodynamic simulation shows characteristic intermittent pulsations of the drag and lift force on the cylinder. At Re = 200 a mix of secondary spanwise three-dimensional instabilities (A and B mode, rib vortices) could be observed. The spanwise wavelength of the rib vortices was found to be about 2–3 cylinder side lengths in the near wake. At Re = 250 the flow appears more organized showing a regular B mode pattern and a spanwise wavelength of about 1 cylinder side length. With an applied magnetic field a quasi-two-dimensional flow can be obtained at low N ≈ 1 due to the strong non-isotropic character of the electromagnetic forces. The remaining vortices have their axes aligned with the magnetic field. With increasing magnetic fields these vortices are further damped due to Hartmann braking. The result that the ‘quasi-two-dimensional’ vortices have a curvature in the direction of the magnetic field can be explained by means of an asymptotic analysis of the governing equations. With very high magnetic fields the time-dependent vortex shedding can be almost completely suppressed. By three-dimensional visualization it was possible to show characteristic paths of the electric current for this kind of flow, explaining the action of the Lorentz forces.

scholarly journals Analysis of Injected Electron Beam Propagation in a Planar Crossed-Field Gap

2021 ◽  
Vol 11 (6) ◽  
pp. 2540
Author(s):  
Ranajoy Bhattacharya ◽  
Adam M. Darr ◽  
Allen L. Garner ◽  
Jim Browning
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Three Dimensional ◽  
One Dimensional ◽  
Field Device ◽  
The Magnetic Field ◽  
A Current

This paper examines basic crossed-field device physics in a planar configuration, specifically electron beam perturbation and instability as a function of variation in magnetic field, and angle between magnetic and electric field. We perform a three-dimensional (3-D) simulation of electron perturbation in a planar crossed-field system using the full 3-D particle trajectory solver in CST Particle Studio (CST-PS). The structure has a length, height, width and anode-sole gap of 15 cm, 2 cm, 10 cm, and 2 cm, respectively. The anode to sole voltage is fixed at 3 kV, and the magnetic field and injected current varied from 0.01 T to 0.05 T and 1.5 mA to 1 A, respectively. The simulations show that applying a magnetic field of 0.05 T makes the beam stable for a critical current density of 94 mA/cm2 for an anode-sole gap of 20 mm. Above this current density, the beam was unstable, as predicted. Introducing a 1° tilt in the magnetic field destabilizes the beam at a current density of 23 mA/cm2, which is lower than the critical current density for no tilt, as predicted by our theory. The simulation results also agree well with prior one-dimensional (1-D) theory and simulations that predict stable bands of current density for a 5° tilt where the beam is stable at low current density (<13.3 mA/cm2), unstable above this threshold, and then stable again at higher current density, (>33 mA/cm2).

scholarly journals ELECTRON BEAM TRANSVERSION MANAGEMENT ON EXIT OF MAGNETIC GUN BY GRADIENT MAGNETIC FIELD

2020 ◽  
pp. 28-32
Author(s):  
A.S. Mazmanishvili ◽  
N.G. Reshetnyak ◽  
V.P. Romas’ko ◽  
I.A. Chertishchev
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Experimental Studies ◽  
Secondary Emission ◽  
Experimental Results ◽  
Beam Diameter ◽  
Gradient Magnetic Field ◽  
Transport Channel ◽  
The Magnetic Field ◽  
Emission Cathode

The results of experimental studies and modeling calculations for controlling the transverse dimensions of an electron beam formed by a magnetron gun with a secondary emission cathode are presented. In the gun, the secondary emission process is launched by a voltage pulse with an amplitude of up to 15 kV supplied to its anode. The dependence of the radial dimensions of the electron beam on the amplitude and gradient of the magnetic field in the transport channel is investigated. It is shown that the obtained experimental results are consistent with the simulation results. The possibility of adjusting the beam diameter by varying the configuration of the magnetic field is established. The experimental results presented indicate the possibility of realizing irradiation of the outer surface of cylindrical samples placed in the region of the gradient magnetic field.

scholarly journals ELECTRON BEAM DYNAMICS AT OUTPUT MAGNETRON GUN IN GRADIENT MAGNETIC FIELD

2019 ◽  
pp. 106-110
Author(s):  
A.S. Mazmanishvili ◽  
N.G. Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Beam Dynamics ◽  
Radial Compression ◽  
Beam Diameter ◽  
Gradient Magnetic Field ◽  
Transport Channel ◽  
Beam Motion ◽  
The Magnetic Field ◽  
Electron Beam Dynamics

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.

scholarly journals DYNAMICS OF THE ELECTRON BEAM GENERATED BY THE MAGNETRON GUN WITH DIFFERENT CONFIGURATIONS OF THE MAGNETIC FIELD IN THE TRANSPORTATION CHANNEL

2021 ◽  
pp. 121-125
Author(s):  
O.S. Mazmanishvili ◽  
M.G. Reshetnyak ◽  
V.P. Romasko ◽  
I.A. Chertishchev
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electron Beam ◽  
Secondary Emission ◽  
Beam Diameter ◽  
Gradient Magnetic Field ◽  
Cathode Voltage ◽  
Transport Channel ◽  
Transportation Channel ◽  
The Magnetic Field

The dynamics of the dimensions of the electron beam generated by the magnetron gun in the particle transport channel and the efficiency of focusing the tubular electron beam in the gradient magnetic field are investigated. The experiments were carried out with magnetron guns with secondary-emission cathodes (cathode diameters 36 and 16 mm, anodes diameters 78 and 36 mm) at cathode voltage of 20...80 kV. Magnetic fields were created both by the solenoid and jointly by the solenoid and the permanent magnet. The dependence of the radial distribution of the beam on metal targets on the amplitude and gradient of the magnetic field along the axis of the system is inves-tigated. The possibility of controlling the beam diameter by varying the magnetic field is shown. The imprints of collimated beams were obtained experimentally on targets located at selected distances. The obtained experimental data agree with the results of numerical simulation. It is shown that with an increase in the amplitude of the gradient magnetic field, the effect of radial focusing of the beam is more pronounced.

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