scholarly journals Особенности применения электронов в исследовании пленок гексаферрита бария на c-сапфире

2021 ◽  
Vol 47 (1) ◽  
pp. 31
Author(s):  
А.Э. Муслимов ◽  
М.Г. Исмаилов ◽  
В.М. Каневский
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Easy Axis ◽  
Film Formation ◽  
High Energy ◽  
Beam Deflection ◽  
Angle Of Incidence ◽  
High Energy Electrons

Processes of film formation (0001) BaFe12O19 on sapphire with ferromagnetic "easy axis" directed along normal to substrate are investigated. Propagation of the beam of high-energy electrons during interaction with the (0001) BaFe12O19 film was studied depending on the angle of incidence of the beam. Deflection of sliding electron beam by magnetic field of (0001) BaFe12O19 film is demonstrated. It is shown that the presence of (0001) BaFe12O19 film on sapphire leads to the redistribution of cathodoluminescence in it mainly to the "red" region. The radiation associated with the film itself was not detected in the experiment.

scholarly journals Detection of TeV Gamma Rays from SN1006

1998 ◽  
Vol 188 ◽  
pp. 121-124 ◽  
Author(s):  
Toru Tanimori
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Gamma Rays ◽  
High Energy ◽  
Shock Acceleration ◽  
Emission Region ◽  
X Ray ◽  
High Energy Electrons ◽  
Tev Gamma Rays ◽  
The Magnetic Field

In spite of the recent progress of high energy gamma-ray astronomy, there still remains quite unclear and important problem about the origin of cosmic rays. Supernova remnants (SNRs) are the favoured site for cosmic rays up to 1016 eV, as they satisfy the requirements such as an energy input rate. But direct supporting evidence is sparse. Recently intense non-thermal X-ray emission from the rims of the Type Ia SNR SN1006 (G327.6+14.6) has been observed by ASCA (Koyama et al. 1995)and ROSAT (Willingale et al. 1996), which is considered, by attributing the emission to synchrotron radiation, to be strong evidence of shock acceleration of high energy electrons up to ~100 TeV. If so, TeV gamma rays would also be expected from inverse Compton scattering (IC) of low energy photons (mostly attributable to the 2.7 K cosmic background photons) by these electrons. By assuming the magnetic field strength (B) in the emission region of the SNR, several theorists (Pohl 1996; Mastichiadis 1996; Mastichiadis & de Jager 1996; Yoshida & Yanagita 1997) calculated the expected spectra of TeV gamma rays using the observed radio/X-ray spectra. Observation of TeV gamma rays would thus provide not only the further direct evidence of the existence of very high energy electrons but also the another important information such as the strength of the magnetic field and diffusion coefficient of the shock acceleration. With this motivation, SN1006 was observed by the CANGAROO imaging air Cerenkov telescope in 1996 March and June, also 1997 March and April.

Migrations of Interstitial Atoms in Semiconductors (Surface Diffusion and Kick-Out Mechanism)

1989 ◽  
Vol 163 ◽  
Author(s):  
Takao Wada ◽  
Akihiro Takeda ◽  
Masaya Ichimura ◽  
Michihiko Takeda
Keyword(s):  
Electron Beam ◽  
Surface Diffusion ◽  
High Energy ◽  
Gaas Substrates ◽  
High Energy Electrons ◽  
Interstitial Atoms

AbstractGe and Zn atoms were introduced into the unirradiated regions of Si at 150°C and GaAs wafers at 50°C, respectively by using the electron-beam doping method. The surfaces of Si and GaAs substrates were covered partially by the overlayers of Ge and Zn sheets, respectively. The only surfaces of the Ge and Zn sheets were irradiated locally. with high energy electrons at 7MeV with the fluences of 5×1017 – 1×1018 electrons cm-2 . Even at a distance of ~10mm from the irradiated overlayers in the Si and GaAs substrates, Ge and Zn atoms respectively, whose interstitials may migrate the unirradiated regions, were detected by SIMS measurements. PL signal due to band-to-acceptor (ZnGa ) transition at 1.48eV becomes observable after annealing at 800°C for 20mm in the unirradiated GaAs region, which is separated from Zn sheet by nearly 10mm.

scholarly journals Fast magnetic energy dissipation in relativistic plasma induced by high order laser modes

2016 ◽  
Vol 4 ◽  
Author(s):  
Y. J. Gu ◽  
Q. Yu ◽  
O. Klimo ◽  
T. Zh. Esirkepov ◽  
S. V. Bulanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Magnetic Energy ◽  
Collisionless Plasma ◽  
High Energy ◽  
Field Energy ◽  
Displacement Current ◽  
Particle In Cell ◽  
Magnetic Field Energy ◽  
High Energy Electrons

Fast magnetic field annihilation in a collisionless plasma is induced by using TEM(1,0) laser pulse. The magnetic quadrupole structure formation, expansion and annihilation stages are demonstrated with 2.5-dimensional particle-in-cell simulations. The magnetic field energy is converted to the electric field and accelerate the particles inside the annihilation plane. A bunch of high energy electrons moving backwards is detected in the current sheet. The strong displacement current is the dominant contribution which induces the longitudinal inductive electric field.

Processing windows for Ti-6Al-4V fabricated by selective electron beam melting with improved beam focus and different scan line spacings

2019 ◽  
Vol 25 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Christoph R. Pobel ◽  
Fuad Osmanlic ◽  
Matthias A. Lodes ◽  
Sebastian Wachter ◽  
Carolin Körner
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
High Energy ◽  
Beam Deflection ◽  
Content Type ◽  
Powder Bed ◽  
Manufacturing Method ◽  
High Speeds ◽  
Selective Electron Beam Melting ◽  
Scan Line

Purpose Selective electron beam melting (SEBM) is a highly versatile powder bed fusion additive manufacturing method. SEBM is characterized by high energy densities which can be applied with nearly inertia free beam deflection at high speeds (<8.000 m/s). This paper aims to determine processing maps for Ti-6Al-4V on an Arcam Q10 machine with LaB6 cathode design. Design/methodology/approach Scan line spacings of 100, 50 and 20 µm in a broad parameter range, focusing on high deflection and build speeds are investigated. Findings There are broad processing windows for dense parts without surface flaws for all scan line spacings which are defined by the total energy input and the area melting velocity. Originality/value The differences and limitations are discussed taking into account the beam properties at high beam energy and velocity as well as evaporation related loss of alloying components.

scholarly journals Bursty emission of whistler waves in association with plasmoid collision

2017 ◽  
Vol 35 (4) ◽  
pp. 885-892 ◽  
Author(s):  
Keizo Fujimoto
Keyword(s):  
Magnetic Field ◽  
Electron Temperature ◽  
Magnetic Reconnection ◽  
High Energy ◽  
Temperature Anisotropy ◽  
Whistler Waves ◽  
High Energy Electrons ◽  
Parallel Direction ◽  
Short Time ◽  
Particle Energization

Abstract. A new mechanism to generate whistler waves in the course of collisionless magnetic reconnection is proposed. It is found that intense whistler emissions occur in association with plasmoid collisions. The key processes are strong perpendicular heating of the electrons through a secondary magnetic reconnection during plasmoid collision and the subsequent compression of the ambient magnetic field, leading to whistler instability due to the electron temperature anisotropy. The emissions have a bursty nature, completing in a short time within the ion timescales, as has often been observed in the Earth's magnetosphere. The whistler waves can accelerate the electrons in the parallel direction, contributing to the generation of high-energy electrons. The present study suggests that the bursty emission of whistler waves could be an indicator of plasmoid collisions and the associated particle energization during collisionless magnetic reconnection.

scholarly journals Electron dynamics during substorm dipolarization in Mercury's magnetosphere

2005 ◽  
Vol 23 (10) ◽  
pp. 3389-3398 ◽  
Author(s):  
D. C. Delcourt ◽  
K. Seki ◽  
N. Terada ◽  
Y. Miyoshi
Keyword(s):  
Magnetic Field ◽  
High Energy ◽  
Expansion Phase ◽  
Earth’S Magnetosphere ◽  
High Energy Electrons ◽  
Earth's Magnetosphere ◽  
Magnetic Field Model ◽  
Particle Simulations ◽  
Field Lines ◽  
The Magnetic Field

Abstract. We examine the nonlinear dynamics of electrons during the expansion phase of substorms at Mercury using test particle simulations. A simple model of magnetic field line dipolarization is designed by rescaling a magnetic field model of the Earth's magnetosphere. The results of the simulations demonstrate that electrons may be subjected to significant energization on the time scale (several seconds) of the magnetic field reconfiguration. In a similar manner to ions in the near-Earth's magnetosphere, it is shown that low-energy (up to several tens of eV) electrons may not conserve the second adiabatic invariant during dipolarization, which leads to clusters of bouncing particles in the innermost magnetotail. On the other hand, it is found that, because of the stretching of the magnetic field lines, high-energy electrons (several keVs and above) do not behave adiabatically and possibly experience meandering (Speiser-type) motion around the midplane. We show that dipolarization of the magnetic field lines may be responsible for significant, though transient, (a few seconds) precipitation of energetic (several keVs) electrons onto the planet's surface. Prominent injections of energetic trapped electrons toward the planet are also obtained as a result of dipolarization. These injections, however, do not exhibit short-lived temporal modulations, as observed by Mariner-10, which thus appear to follow from a different mechanism than a simple convection surge.

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