scholarly journals Simulation of physics background in Super c-tau factory detector

2019 ◽  
Vol 212 ◽  
pp. 01009 ◽  
Author(s):  
L Shekhtman ◽  
F Ignatov ◽  
V Tayursky
Keyword(s):  
Magnetic Field ◽  
Beam Energy ◽  
Photon Emission ◽  
Absorbed Dose ◽  
Drift Chamber ◽  
Bremsstrahlung Photon ◽  
Two Photon ◽  
Electron Positron ◽  
The Magnetic Field ◽  
Conceptual Design Report

Simulation of background particle fluxes generated by colliding beams is performed with FLUKA package for the Super C-Tau factory Detector (SCTD). Two processes are considered as main sources of luminosity generated background: two-photon production of electron-positron pairs and Bha-Bha scattering with bremsstrahlung photon emission (radiative Bha-Bha). The SCTD geometry is described corresponding to the last version of the Conceptual Design Report. The magnetic field based on the calculation in ANSYS is introduced in the model. Main results of the simulation for beam energy of 3 GeV, luminosity of 1035 cm−2s−1 and 1.5 T magnetic field are the following: charged particle fluence in the region of the Inner Tracker (radius 5cm -20 cm, Z between -30cm and 30 cm) is between 105 particles/(cm2s) and ∼103 particles/(cm2s); 1-MeV neutron equivalent fluence for Si in the regions corresponding to electronics of the Inner Tracker and the Drift Chamber is below 1011 n/(cm2y) and absorbed dose is below 100 Gy/y in the hottest regions of the detector.

scholarly journals Magnetic dominance of axion electrodynamics: photon capture effect and anisotropy of Coulomb potential

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
S. Villalba-Chávez ◽  
A. E. Shabad ◽  
C. Müller
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Strong Magnetic Field ◽  
Coulomb Potential ◽  
Heat Radiation ◽  
Radiation Mechanism ◽  
Electron Positron ◽  
Coulomb Singularity ◽  
Relativistic Hydrogen ◽  
The Magnetic Field

AbstractFor magnetic fields larger than the characteristic scale linked to axion-electrodynamics, quantum vacuum fluctuations due to axion-like fields can dominate over those associated with the electron-positron fields. This conjecture is explored by investigating both the axion-modified photon capture by a strong magnetic field and the Coulomb potential of a static pointlike charge. We show that in magnetic fields characteristic of neutron stars $$\sim 10^{13}$$ ∼ 10 13 –$$10^{15}\;\mathrm{G}$$ 10 15 G , the capture of gamma photons prior to the production of a pair can prevent the existence of an electron-positron plasma, essential for explaining the pulsar radiation mechanism. This incompatibility is used to limit the axion parameter space. Our bounds improve existing outcomes in the region of mass $$m\sim 10^{-10}$$ m ∼ 10 - 10 –$$10^{-5}\;{\mathrm{eV}}$$ 10 - 5 eV . The effect of capture, known in QED as relating to gamma-quanta, is extended in axion electrodynamics to include X-ray photons with the result that a specially polarized part of the heat radiation from the surface is canalized along the magnetic field. Besides, we find that in the regime in which the dominance takes place, the running QED coupling depends on the field strength and the modified Coulomb potential is of Yukawa-type in the direction perpendicular to the magnetic field at distances much smaller than the axion Compton wavelength, while along the field it follows approximately the Coulomb law at any length scale. Despite the Coulomb singularity manifested in the latter case, we argue that the ground-state energy of a non-relativistic hydrogen atom placed in a strong magnetic field turns out to be bounded due to the nonrenormalizable feature of axion-electrodynamics.

scholarly journals Photons in a cold axion background and strong magnetic fields: Polarimetric consequences

2015 ◽  
Vol 30 (17) ◽  
pp. 1550099 ◽  
Author(s):  
Domènec Espriu ◽  
Albert Renau
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Galactic Halo ◽  
Local Density ◽  
Polarization Plane ◽  
Strong Magnetic Fields ◽  
Two Photon ◽  
Main Effect ◽  
Optical Table ◽  
The Magnetic Field

In this work, we analyze the propagation of photons in an environment where a strong magnetic field (perpendicular to the photon momenta) coexists with an oscillating cold axion background with the characteristics expected from dark matter in the galactic halo. Qualitatively, the main effect of the combined background is to produce a three-way mixing among the two photon polarizations and the axion. It is interesting to note that in spite of the extremely weak interaction of photons with the cold axion background, its effects compete with those coming from the magnetic field in some regions of the parameter space. We determine (with one plausible simplification) the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments.

Surface waves in magnetized quantum electron-positron plasmas

2009 ◽  
Vol 76 (1) ◽  
pp. 87-99 ◽  
Author(s):  
A.P. MISRA ◽  
N.K. GHOSH ◽  
P.K. SHUKLA
Keyword(s):  
Magnetic Field ◽  
Surface Waves ◽  
Boundary Surface ◽  
Electron Positron ◽  
Electrons And Positrons ◽  
Quantum Electron ◽  
Special Cases ◽  
General Dispersion ◽  
Singular Wave ◽  
The Magnetic Field

AbstractThe dispersion properties of electrostatic surface waves propagating along the interface between a quantum magnetoplasma composed of electrons and positrons, and vacuum are studied by using a quantum magnetohydrodynamic plasma model. The general dispersion relation for arbitrary orientation of the magnetic field and the propagation vector is derived and analyzed in some special cases of interest (viz. when the magnetic field is directed parallel and perpendicular to the boundary surface). It is found that the quantum effects facilitate the propagation of electrostatic surface modes in a dense magnetoplasma. The effect of the external magnetic field is found to increase the frequency of the quantum surface wave. The existence of a singular wave on the boundary surface is also proved, and its properties are analyzed numerically. It is shown that the new wave characteristics appear due to the Rayleigh type of the wave.

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.

Magnetic-field-enhanced spontaneous two-photon emission of hydrogenic atoms

1993 ◽  
Vol 48 (1) ◽  
pp. 516-524 ◽  
Author(s):  
P. C. Stancil ◽  
G. E. Copeland
Keyword(s):  
Magnetic Field ◽  
Photon Emission ◽  
Two Photon

Pulsar magnetospheres

1992 ◽  
Vol 341 (1660) ◽  
pp. 93-104 ◽  
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Photon Emission ◽  
Rotation Period ◽  
Primary Electron ◽  
Rotation Axes ◽  
Polar Caps ◽  
Electron Positron ◽  
Field Lines ◽  
Secular Increase

The energy loss from the neutron star - as inferred from the secular increase in rotation period - is much greater than that emitted in either the radio or the other observed wavelengths. A primary motivation of magnetospheric theory is to trace the mode in which this energy and the associated angular momentum are in fact carried off from active pulsars. This review concentrates on the special case in which the magnetic and rotation axes are aligned. Electrons emitted from the polar caps are accelerated to highly relativistic energies by the electric force and simultaneously pick up angular momentum from the magnetic torque. Some process of angular momentum dissipation occurring beyond the light-cylinder is then required, both to yield the continuous spin-down of the star, and also to allow the electrons to cross magnetic field lines and so complete their circuits back to the star. Within the framework of classical physics, this could occur if most of the spin-down energy is lost through incoherent photon emission in an equatorial domain beyond the lightcylinder, but this would generate y-radiation far in excess of that observed. Transport away of the angular momentum via a relativistic wind requires the generation of a quasi-neutral plasma. Gamma-rays emitted by outflowing electrons will produce electron-positron pairs in the strong magnetic field near the star, and highly energetic electrons returning to the star may also generate a mixed plasma by pair production or by surface spallation. Coupling with the circulating primary electron current may then ensure that the dominant angular momentum loss is via the wind rather than through photon emission.

SELF-MAGNETIZATION IN ELECTROWEAK VACUUM AND IN VERY DENSE SYSTEMS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 168-175
Author(s):  
HUGO PÉREZ ROJAS ◽  
ELIZABETH RODRÍGUEZ QUERTS
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
External Field ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
W Bosons ◽  
Large Density ◽  
Electron Positron ◽  
Vector Bosons ◽  
The Magnetic Field

For charged vector bosons (W bosons) of mass mw, magnetization diverges for B → Bcw, which suggests that if the magnetic field is large enough, it can be self-consistently maintained. For photons bearing an anomalous magnetic moment, having a sufficiently large density, their contribution to magnetization might become of the same order than the applied external field, leading also to self-magnetization. We discuss these models in connection to the case of radiation in equilibrium at high temperature (T ~ mc2) coexisting with hot magnetized electron-positron pairs.

scholarly journals The Nature of Pulsar Subpulse Drift

1991 ◽  
Vol 44 (5) ◽  
pp. 573 ◽  
Author(s):  
AZ Kazbegi ◽  
GZ Machabeli ◽  
GI Melikidze
Keyword(s):  
Magnetic Field ◽  
Angular Velocity ◽  
Large Scale ◽  
Primary Particle ◽  
Particle Beam ◽  
Drift Waves ◽  
Electron Positron ◽  
Field Lines ◽  
The Magnetic Field ◽  
Open Magnetic Field

A possible mechanism for the explanation of pulsar subpulse drift is suggested. In the region of the open magnetic field lines the existence of an electron-positron plasma penetrated by a primary particle beam is assumed. There is a possibility of excitation of large-scale drift waves propagating transversely to the magnetic field lines. These waves can affect the fulfilment of the radio-wave generation conditions. If the pulsar angular velocity is near to the frequency of the drift waves one should observe regular drift phenomena.

scholarly journals Vector Resolved Energy Fluxes and Collisional Energy Losses in Magnetic Nozzle Radiofrequency Plasma Thrusters

2021 ◽  
Vol 9 ◽  
Author(s):  
Kazuma Emoto ◽  
Kazunori Takahashi ◽  
Yoshinori Takao
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Beam Energy ◽  
Particle Energy ◽  
Energy Losses ◽  
Plasma Energy ◽  
Collisional Energy ◽  
Magnetic Nozzle ◽  
The Magnetic Field

Energy losses in a magnetic nozzle radiofrequency plasma thruster are investigated to improve the thruster efficiency and are calculated from particle energy losses in fully kinetic simulations. The simulations calculate particle energy fluxes with a vector resolution including the plasma energy lost to the dielectric wall, the plasma beam energy, and the divergent plasma energy in addition to collisional energy losses. As a result, distributions of energy losses in the thruster and the ratios of the energy losses to the input power are obtained. The simulation results show that the plasma energy lost to the dielectric is dramatically suppressed by increasing the magnetic field strength, and the ion beam energy increases instead. In addition, the divergent ion energy and collisional energy losses account for approximately 4%–12% and 30%–40%, respectively, regardless of the magnetic field strength.

scholarly journals Primordial Nucleosynthesis with a background magnetic field

2020 ◽  
Vol 227 ◽  
pp. 02003
Author(s):  
Yudong Luo ◽  
Toshitaka Kajino ◽  
Motohiko Kusakabe ◽  
Michael A Famiano
Keyword(s):  
Magnetic Field ◽  
Early Universe ◽  
Big Bang ◽  
Detailed Calculation ◽  
Big Bang Nucleosynthesis ◽  
Capture Reaction ◽  
Primordial Nucleosynthesis ◽  
Electron Positron ◽  
Background Magnetic Field ◽  
The Magnetic Field

We present our recent detailed calculation of the impacts from a background magnetic field on Big Bang Nucleosynthesis (BBN). Namely, the magnetic field impacts on the electron-positron thermodynamics, time temper-ature relation and the screening potential of the early Universe. Most interest-ingly, we investigated the electron-positron relativistic screening potential with the background magnetic field, such potential might lead to a non trivial effect on the electron capture reaction which could finally affect the neutron to proton ratio.

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