scholarly journals TWO DIPOLE MAGNETIC SYSTEMS FOR TECHNOLOGICAL ELECTRON ACCELERATOR

2019 ◽  
pp. 9-12
Author(s):  
V.А. Bovda ◽  
А.М. Bovda ◽  
I.S. Guk ◽  
А.N. Dovbnya ◽  
S.G. Kononenko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Linear Accelerator ◽  
Electron Accelerator ◽  
Effective Length ◽  
Dipole Magnet ◽  
Permanent Magnetic Field ◽  
Magnetic Systems ◽  
Maximum Magnetic Field ◽  
The Magnetic Field

For a 10 MeV technological accelerator, a dipole magnet with a permanent magnetic field was created using the SmCo alloy. The maximum magnetic field in the magnet gap was 0.3 T. The magnet is designed to measure the energy of the beam and to adjust the accelerator for a given energy. For a linear accelerator with an energy of 23 MeV, a dipole magnet based on the Nd-Fe-B alloy was developed and fabricated. It was designed to rotate the electron beam at a 90 degrees. The magnetic field in the dipole magnet along the path of the beam was 0.5 T. The effective length of the magnet was 242 mm.

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

scholarly journals Precision Analysis and Design of Rotating Coil Magnetic Measurements System

2020 ◽  
Vol 10 (23) ◽  
pp. 8454
Author(s):  
Soontorn Odngam ◽  
Chaiyut Preecha ◽  
Prapaiwan Sanwong ◽  
Woramet Thongtan ◽  
Jiraphon Srisertpol
Keyword(s):  
Magnetic Field ◽  
Control System ◽  
Magnetic Measurements ◽  
Speed Control ◽  
Measuring Instruments ◽  
Dipole Magnet ◽  
Analysis And Design ◽  
Speed Control System ◽  
The Impact ◽  
The Magnetic Field

This research presents the design and construction of measuring instruments for a dipole magnetic field using a rotating coil technique. This technique is a closed-loop speed-control system where a Proportional-Integral (PI) controller works together with the intensity measurement of the magnetic field through the rotating coil. It was used to analyze the impact on the accuracy of the electromagnetic at speed ranges of 60, 90, and 120 rpm. The error estimation in the measurement of the normal dipole and skew dipole magnet caused by the steady-state error of the speed control system and the rotational search coil in whirling motion are demonstrated. Rotating unbalance, shaft coupling, and misalignment from its setup disturbed the performance of the speed control system as a nonlinear system.

scholarly journals Accretion Disc Formation in Intermediate Polars

1996 ◽  
Vol 158 ◽  
pp. 161-164
Author(s):  
G. A. Wynn ◽  
A. R. King
Keyword(s):  
Magnetic Field ◽  
Accretion Disc ◽  
Local Magnetic Field ◽  
Magnetic Systems ◽  
X Ray ◽  
Accretion Flow ◽  
Intermediate Polars ◽  
X Ray Binaries ◽  
The Magnetic Field ◽  
Disc Formation

The large-scale accretion flow in the intermediate polars (IPs) is still a matter of vigorous debate. It is known that the magnetic field of the white dwarf (WD) controls the accretion flow close to the surface, channeling the plasma onto the polecaps and giving rise to X-ray emission modulated at the WD spin period (Pspin). After their discovery it was assumed that IPs were the WD analogues of the pulsing X-ray binaries, where a magnetic neutron star accretes from a disrupted accretion disc. However, a number of authors have pointed out that the criteria for disc formation in IPs are less certain than those for the X-ray binaries.The simplest possible criterion for disc formation in a binary is that the accretion flow should be able to orbit freely about the primary star (see Frank, King & Raine 1991 for a review). In non-magnetic systems this is merely the condition that the minimum approach distance of the free stream (Rmin) should exceed the radius of the primary. The situation in magnetic systems is more complex, as the magnetic field of the primary presents an obstacle to the infalling accretion stream. In many treatments of IPs it is assumed that the plasma stream is able to orbit freely about the WD until the ram pressure of the stream is of the same order as the magnetic pressureρv2~B2/8π, whereρis the stream density,vthe stream velocity andBthe local magnetic field strength. This condition fixes the magnetospheric radius,Rmag, inside which the magnetic field is assumed to thread the stream material and direct the accretion flow along the fieldlines.

Simulation of bunched electron-beam acceleration by the cylindrical TE113 microwave field

2019 ◽  
Vol 34 (36) ◽  
pp. 1942030
Author(s):  
E. A. Orozco ◽  
J. D. González ◽  
J. R. Beltrán ◽  
V. E. Vergara
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Microwave Field ◽  
Inhomogeneous Magnetic Field ◽  
X Ray ◽  
Particle In Cell ◽  
Magnetic Field Profile ◽  
Detailed Simulation ◽  
The Magnetic Field ◽  
Particle Approximation

We report a detailed simulation of a bunched electron-beam accelerated in a TE[Formula: see text] cylindrical cavity immersed in a static inhomogeneous magnetic field using a relativistic full electromagnetic particle-in-cell (PIC). This type of acceleration concept is known as Spatial AutoResonance Acceleration (SARA) in which the magnetic field profile is such that it keeps the electron-beam in the acceleration regime along their trajectories. In this work, the numerical experiments are carried out including a bunched electron-beam with the concentrations in the range [Formula: see text]–[Formula: see text][Formula: see text]cm[Formula: see text] in a TE[Formula: see text] cylindrical microwave field, at a frequency of 2.45 GHz and an amplitude of 15 kV/cm. The electron energy reaches values up to 250 keV without significant unfocusing effect that can be used as a basis to produce hard X-ray. Additionally, a comparison between the data obtained from the full electromagnetic PIC simulations and the results derived from the relativistic Newton–Lorentz equation in a single particle approximation is carried out.

PERTURBATION THEORY FOR THE ALFVÉN WAVE

1995 ◽  
Vol 09 (22) ◽  
pp. 2857-2898 ◽  
Author(s):  
Z. YOSHIDA ◽  
S.M. MAHAJAN
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Electron Beam ◽  
Continuous Spectrum ◽  
Point Spectrum ◽  
Alfven Wave ◽  
Wave Number ◽  
Ambient Magnetic Field ◽  
Field Lines ◽  
The Magnetic Field

The Alfvén wave is the dominant low frequency transverse mode of a magnetized plasma. The Alfvén wave propagates along the magnetic field, and displays a continuous spectrum even in a bounded plasma. This is essentially due to the degeneracy of the wave characteristics, i.e. the frequency (ω) is primarily determined by the wave number in the direction parallel to the ambient magnetic field (k||) and is independent of the perpendicular wavenumbers. The characteristics, that are the direction along which the wave energy propagates, are identical to the ambient magnetic field lines. Therefore, the spectral structure of the Alfvén wave has a close relationship with the geometric structure of the magnetic field lines. In an inhomogeneous plasma, the Alfvén resonance (ω−cAk||=0; cA is the phase velocity of the Alfvén wave) constitutes a singularity for the defining wave equation; this results in a singular eigenfunction corresponding to the continuous spectrum. The aim of this review is to present an overview of the perturbation theory for the Alfvén wave. Emphasis is placed on those perturbations of the continuous spectrum which lead to the creation of point spectra. Such qualitative changes in the spectrum are relevant to many plasma phenomena. The first category of perturbations consists of nonideal effects such as the finite conductivity, kinetic effects arising from the finite electron inertia, and finite gyroradius. These effects add singular perturbations to the mode equation, and modify the spectrum dramatically. These modification, viz. the conversion of the continuous to the point spectrum, can lead to interesting physical phenomenon. A case in point is that of an electron beam propagating in a plasma which Cherenkov emits a left-hand circularly polarized Alfvén wave. The helicity of the ambient magnetic field imparts a frequency shift to the eigenmodes changing the critical velocity for Cherenkov emission. It, then, becomes possible for a sub-Alfvénic electron beam to excite a nonsingular Alfvén wave corresponding to a point spectrum. The second category comprises of geometric perturbations associated with higher dimensional inhomogeneity of the ambient field. Forbidden bands occur when a periodic modulation is applied. In a chaotic magnetic field, the weak localization of the wave occurs, resulting in a point spectrum.

scholarly journals Низкоэнергетическое состояние электронного пучка в коаксиальном диоде с однородным анодом и неоднородным профилем магнитного поля

2018 ◽  
Vol 44 (20) ◽  
pp. 102
Author(s):  
А.В. Громов ◽  
М.Б. Гойхман ◽  
Н.Ф. Ковалев ◽  
А.В. Палицин ◽  
M.I. Fuks ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Energy State ◽  
Field Configuration ◽  
Low Energy ◽  
Moderate Magnetic Field ◽  
First Time ◽  
Cylindrical Anode ◽  
The Magnetic Field ◽  
Reflection Plane

AbstractThe possible formation of an extended low-energy state of electron beam in a coaxial diode with homogeneous cylindrical anode and moderate magnetic field with inhomogeneous profile is demonstrated for the first time. It is established that, depending on the magnetic field configuration, virtual cathodes (VCs) of two types can be formed: (i) a stationary VC with a localized reflection plane and (ii) a moving VC with a two-stream low-energy state of the electron beam.

scholarly journals Nd-Fe-B MAGNETS UNDER ELECTRON IRRADIATION WITH THE ENERGY OF 23 MeV

2020 ◽  
pp. 23-27
Author(s):  
V.A. Bovda ◽  
А.М. Bovda ◽  
I.S. Guk ◽  
A.N. Dovbnya ◽  
V.N. Lyashchenko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Magnetic Flux ◽  
Electron Irradiation ◽  
Reference Sample ◽  
Absorbed Dose ◽  
Initial State ◽  
Magnetic Performance ◽  
And Control ◽  
The Magnetic Field

Four Nd-Fe-B magnets underwent irradiation under 23 MeV electron beam. Nd-Fe-B magnets were magnetized to the technical saturation in the magnetic field of 3.5 T before electron treatment. Two Nd-Fe-B samples (1 and 2) were exposed to the direct electron beam with the energy of 23 MeV. Sample 2 was shielded by tungsten converter. The thickness of the tungsten converter was 4.72 mm. The absorbed dose for the samples was 16 GRad. Sample 3 was subjected to bremsstrahlung of electron irradiation with the energy of 23 MeV. Sample 4 was used as a reference sample for calibration and control measurements. While magnetic flux of sample under direct electron beam of 23 MeV was changed significantly, sample 2 showed the change of magnetic flux to a less degree. Magnetic performance of sample 3 corresponded closely to the initial state.

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.

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