scholarly journals Hilltop Inflation and Generation of Helical Magnetic Field

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 26
Author(s):  
Sumanta Chakraborty ◽  
Supratik Pal ◽  
Soumitra SenGupta
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Quantum Electrodynamics ◽  
Anomaly Cancellation ◽  
Significant Strength ◽  
Intergalactic Magnetic Field ◽  
Helical Magnetic Field ◽  
Sufficient Strength ◽  
Large Parameter Space ◽  
The Magnetic Field

Primordial magnetic field generated in the inflationary era can act as a viable source for the present day intergalactic magnetic field of sufficient strength. We present a fundamental origin for such a primordial generation of the magnetic field, namely through anomaly cancellation of U(1) gauge field in quantum electrodynamics in the context of hilltop inflation. We have analysed at length the power spectrum of the magnetic field, thus generated, which turns out to be helical in nature. We have also found that magnetic power spectrum has significant scale-dependence giving rise to a non-trivial magnetic spectral index, a key feature of this model. Interestingly, there exists a large parameter space, where magnetic field of significant strength can be produced.

The distribution function of diffuse ions and the magnetic field power spectrum upstream of Earth's bow shock

1987 ◽  
Vol 14 (7) ◽  
pp. 681-684 ◽  
Author(s):  
E. Möbius ◽  
M. Scholer ◽  
N. Sckopke ◽  
H. Lühr ◽  
G. Paschmann ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Distribution Function ◽  
Power Spectrum ◽  
Bow Shock ◽  
Earth’S Bow Shock ◽  
The Magnetic Field

scholarly journals Reading M87's DNA: A Double Helix Revealing a Large-scale Helical Magnetic Field

2021 ◽  
Vol 923 (1) ◽  
pp. L5
Author(s):  
Alice Pasetto ◽  
Carlos Carrasco-González ◽  
José L. Gómez ◽  
José-Maria Martí ◽  
Manel Perucho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Double Helix ◽  
High Sensitivity ◽  
Polarization Degree ◽  
Very Large Array ◽  
Wide Range ◽  
Helical Magnetic Field ◽  
Helical Configuration ◽  
The Magnetic Field

Abstract We present unprecedented high-fidelity radio images of the M87 jet. We analyzed Jansky Very Large Array broadband full-polarization radio data from 4 to 18 GHz. The observations were taken with the most extended configuration (A configuration), which allows the study of the emission of the jet up to kiloparsec scales with a linear resolution of ∼10 pc. The high sensitivity and resolution of our data allow us to resolve the jet width. We confirm a double-helix morphology of the jet material between ∼300 pc and ∼1 kpc. We found a gradient of the polarization degree with a minimum at the projected axis and maxima at the jet edges and a gradient in the Faraday depth with opposite signs at the jet edges. We also found that the behavior of the polarization properties along the wide range of frequencies is consistent with internal Faraday depolarization. All of these characteristics strongly support the presence of a helical magnetic field in the M87 jet up to 1 kpc from the central black hole, although the jet is most likely particle-dominated at these large scales. Therefore, we propose a plausible scenario in which the helical configuration of the magnetic field has been maintained to large scales thanks to the presence of Kelvin–Helmholtz instabilities.

Band structure for relativistic charge carriers submitted to a helical magnetic field

2021 ◽  
pp. 2150141
Author(s):  
D. Martínez ◽  
J. A. Reyes ◽  
G. Reyes ◽  
C. G. Avendaño
Keyword(s):  
Magnetic Field ◽  
Band Structure ◽  
Charge Carriers ◽  
Momentum Operator ◽  
Rotating Magnetic Field ◽  
Band Gaps ◽  
Spatial Period ◽  
System Parameters ◽  
Helical Magnetic Field ◽  
The Magnetic Field

In this paper, we consider a clockwise rotating magnetic field around the [Formula: see text]-axis and charge carriers which impinge normally to the [Formula: see text] plane. We obtained analytically the spectrum of the momentum operator [Formula: see text] and found the existence of a band structure from which the movement of these charge carries is filtered according to the spatial period of the magnetic field or its intensity. Also we exhibit the existence of three band gaps (one total or primary and two partials) whose width depends on the system parameters.

scholarly journals PARSEC-SCALE INVESTIGATION OF THE MAGNETIC FIELD STRUCTURE OF SEVERAL AGN JETS

2008 ◽  
Vol 17 (09) ◽  
pp. 1553-1560 ◽  
Author(s):  
S. P. O'SULLIVAN ◽  
D. C. GABUZDA
Keyword(s):  
Magnetic Field ◽  
Faraday Rotation ◽  
Reliable Determination ◽  
Long Baseline ◽  
Central Engine ◽  
Relativistic Jet ◽  
Rotation Measure ◽  
Transverse Rotation ◽  
Helical Magnetic Field ◽  
The Magnetic Field

Multi-frequency (4.6, 5, 5.5, 8, 8.8, 13, 15, 22 & 43 GHz) polarization observations of six "blazars" were obtained on the American Very Long Baseline Array (VLBA) over a 24-hr period on 2 July 2006. Observing at several frequencies, separated by short and long intervals, enabled reliable determination of the distribution of Faraday rotation on a range of scales. In all cases the magnitude of the RM increases in the higher frequency observations, implying that the electron density and/or magnetic field strength is increasing as we get closer to the central engine. After correcting for Faraday rotation, the polarization orientation in the jet is either parallel or perpendicular to the jet direction. A transverse rotation measure (RM) gradient was detected in the jet of 0954+658, providing evidence for the presence of a helical magnetic field surrounding the jet. For three of the sources (0954+658, 1418+546, 2200+420), the sign of the RM in the core region changes in different frequency-intervals, indicating that the line-of-sight component of the magnetic field is changing with distance from the base of the jet. We suggest an explanation for this in terms of bends in a relativistic jet surrounded by a helical magnetic field; where there is no clear evidence for pc-scale bends, the same effect can be explained by an accelerating/decelerating jet.

Modulation of low-rigidity cosmic rays and the power spectrum of the interplanetary magnetic field in 1962 and 1965

1968 ◽  
Vol 46 (10) ◽  
pp. S950-S953 ◽  
Author(s):  
J. R. Jokipii
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Power Spectrum ◽  
Interplanetary Magnetic Field ◽  
Power Spectra ◽  
Cosmic Ray ◽  
Mean Free Path ◽  
Cosmic Ray Modulation ◽  
Magnetometer Data ◽  
The Magnetic Field

The observed change in cosmic-ray modulation from 1963–64 to 1965 may be associated with a corresponding change in the magnetic-field power spectra between 1962 and 1965, as obtained from Mariner 2 and Mariner 4 magnetometer data, respectively. It is further suggested that the diffusion mean-free-path λ may approach a constant value approximately equal to the correlation length of the magnetic field for very-low-rigidity particles.

MIRROR BIREFRINGENCE IN A FABRY-PEROT CAVITY AND THE DETECTION OF VACUUM BIREFRINGENCE IN A MAGNETIC FIELD

1995 ◽  
Vol 10 (28) ◽  
pp. 2125-2134 ◽  
Author(s):  
T.C.P. CHUI ◽  
M. SHAO ◽  
D. REDDING ◽  
Y. GURSEL ◽  
A. BODEN
Keyword(s):  
Magnetic Field ◽  
Quantum Electrodynamics ◽  
State Of The Art ◽  
Beat Frequency ◽  
Polarization Rotation ◽  
High Susceptibility ◽  
First Order ◽  
Fabry Perot ◽  
High Finesse ◽  
The Magnetic Field

Quantum electrodynamics (QED) theory predicts that vacuum under the influence of a strong magnetic field is birefringence. Recently, several groups have proposed to used a high finesse Fabry—Perot cavity to increase the average path length of the light in the magnetic field. This together with the state-of-the-art dipole magnets, should bring the effect within reach of observation. However, the mirrors used in the FP are known to have intrinsic birefringence which is of orders of magnitude larger than the birefringence of the vacuum. In this letter, we analyze the effect of uncontrollable variations of mirror birefringence on two recently proposed optical schemes. The first scheme,1 which we called the frequency scheme, is based on measurement of the beat frequency of two orthogonal polarized laser beams in the cavity. We show that mirror birefringence contributes to the detection uncertainties in first order, resulting in a high susceptibility to variations of its value. In the second scheme, which we called the polarization scheme, laser polarized at 45° relative to the B-field is injected into the cavity. The ellipticity and polarization rotation of the light exiting the cavity is measured.2 Under this scheme, mirror birefringence contributes as a correction of the QED effect, greatly reducing its sensitivity to the undesirable changes.

Quantum electrodynamics between conducting plates II. Spin-dependent effects in neutral atoms

1972 ◽  
Vol 326 (1565) ◽  
pp. 255-275 ◽  
Keyword(s):  
Magnetic Field ◽  
Quantum Electrodynamics ◽  
Hyperfine Splitting ◽  
Neutral Atom ◽  
Parallel Plates ◽  
Bohr Radius ◽  
Upper Limit ◽  
Relativistic Calculation ◽  
Bound Electron ◽  
The Magnetic Field

We consider the spin-dependent changes in the electromagnetic energy of a system when the system is inserted between infinite perfectly conducting parallel plates, separated by a distance L . For practicable values of the magnetic field and of L , the change δμ in the magnetic moment μ of an electron bound in a neutral atom is of the order δμ/μ ~ (μ/ L ) 2 , where h = 1 = c . The change A v in the hyperfine splitting v is of the order A v/v ≈ ( a/L ) 3 , with a the Bohr radius; this falls many orders of magnitude short of the experimental upper limit of Guttrich & Billman. We show that, surprisingly, a non-relativistic calculation yields correct results for a bound electron, though for a free electron one needs a fully relativistic calculation, to be reported separately.

scholarly journals Strong magnetic fields in gauge theories

2021 ◽  
Vol 18 (2 Jul-Dec) ◽  
Author(s):  
Hugo Celso Pérez Rojas ◽  
Jorge Luis Acosta Ávalo
Keyword(s):  
Magnetic Field ◽  
Quantum Electrodynamics ◽  
Chemical Potential ◽  
Polarization Operator ◽  
Cpt Invariance ◽  
Spatial Symmetry ◽  
Photon Propagation ◽  
Self Energy ◽  
The Standard Model ◽  
The Magnetic Field

The problem of photon propagation in a medium in presence of a strong magnetic field in the frame of quantum electrodynamics is discussed in the present paper, based on previous literature in this area. The breaking of the spatial symmetry by the magnetic field determine the existence of a set of basic vectors and tensors which must satisfy the gauge and CPT invariance of quantum electrodynamics. The charge symmetric and non-symmetric cases are discussed. In the second case the Faraday effect is produced. A chiral current arises, associated to a pseudovector eigenvector ofthe polarization operator (due to the breaking of the spatial symmetry by the external magnetic field), related to the so-called axial anomaly. The path integrals and functional derivation are widely used to obtain the self-energy and vertex operators, and the Dyson equations. The inadequate introduction of a chiral chemical potential in the standard model is discussed for the Weinberg-Salam model for electroweak interactions.

scholarly journals Observational constraints on the magnetic field of the bright transient Be/X-ray pulsar SXP 4.78

2019 ◽  
Vol 490 (3) ◽  
pp. 3355-3364
Author(s):  
Andrey N Semena ◽  
Alexander A Lutovinov ◽  
Ilya A Mereminskiy ◽  
Sergey S Tsygankov ◽  
Andrey E Shtykovsky ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Power Spectrum ◽  
Magnetic Field Strength ◽  
Timing Analysis ◽  
Rapid Evolution ◽  
Periodic Oscillation ◽  
X Ray ◽  
The Magnetic Field

ABSTRACT We report results of the spectral and timing analysis of the Be/X-ray pulsar SXP 4.78 using the data obtained during its recent outburst with NuSTAR, Swift, Chandra, and NICER observatories. Using an overall evolution of the system luminosity, spectral analysis, and variability power spectrum we obtain constraints on the neutron star magnetic field strength. We found a rapid evolution of the variability power spectrum during the rise of the outburst, and absence of the significant changes during the flux decay. Several low frequency quasi-periodic oscillation features are found to emerge on the different stages of the outburst, but no clear clues on their origin were found in the energy spectrum and overall flux behaviour. We use several indirect methods to estimate the magnetic field strength on the neutron star surface and found that most of them suggest magnetic field B ≲ 2 × 1012 G. The strictest upper limit comes from the absence of the cyclotron absorption features in the energy spectra and suggests relatively weak magnetic field B < 6 × 1011 G.)

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