scholarly journals PHOTON-PAIR CONVERSION INTO NEUTRINOS IN A STRONG MAGNETIC FIELD

2001 ◽  
Vol 16 (25) ◽  
pp. 1659-1665 ◽  
Author(s):  
A. V. KUZNETSOV ◽  
N. V. MIKHEEV
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Strong Magnetic Field ◽  
Asymptotic Form ◽  
Axial Vector ◽  
Electroweak Interaction ◽  
The Other ◽  
The Standard Model ◽  
Loop Amplitude ◽  
The Magnetic Field

A general analysis of the three-vertex loop amplitude in a strong magnetic field, based on the asymptotic form of the electron propagator in the field, is performed. In order to investigate the photon–neutrino process [Formula: see text], the vertex combinations of the scalar–vector–vector (SVV), pseudoscalar–vector–vector (PVV), three-vector (VVV), and axial-vector–vector–vector (AVV) types are considered. It is shown that only the SVV amplitude grows linearly with the magnetic field strength, while in the other amplitudes, PVV, VVV and AVV, the linearly growing terms are canceled. The process [Formula: see text] is investigated in the left–right-symmetric extension of the standard model of electroweak interaction, where the effective scalar νν e e coupling could exist. Possible astrophysical manifestations of the considered process are discussed.

Schwingung eines Plasmazylinders in einem axialen Magnetfeld II

1960 ◽  
Vol 15 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Klaus Körper
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
External Magnetic Field ◽  
Field Strength ◽  
Axial Magnetic Field ◽  
Surface Current ◽  
The Other ◽  
Plasma Cylinder ◽  
Resonance Frequencies ◽  
The Magnetic Field

Radial oscillations are excited in a homogeneous infinite plasma cylinder in a homogeneous axial magnetic field by a surface current which is homogeneous in the axial and azimuthal directions. The modes of oscillations corresponding to the axial and azimuthal components of current are not coupled, and so they may be analysed separately. The magnetic field in the plasma and vacuum is obtained, and the indices of refraction for both types of oscillations are discussed thoroughly. When the currents are parallel to the external magnetic field, the oscillations are characterized by the refractive index of Eccles. On the other hand, when the current is perpendicular to the magnetic field two resonance frequencies exist, which depend on the density of the plasma and the magnetic field strength. — In the latter case the radial characteristic oscillations of the plasma cylinder in an external magnetic field are considered.

scholarly journals Detection of magnetic fields in He-rich early B-type stars using HARPSpol

2018 ◽  
Vol 618 ◽  
pp. L2 ◽  
Author(s):  
S. P. Järvinen ◽  
S. Hubrig ◽  
I. Ilyin ◽  
M. Schöller ◽  
M. F. Nieva ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Longitudinal Magnetic Field ◽  
High Accuracy ◽  
Photometric Data ◽  
The Other ◽  
High Spectral Resolution ◽  
Periodic Modulation ◽  
First Time ◽  
The Magnetic Field

Aims. We focus on early-B type stars with helium overabundance, for which the presence of a magnetic field has not previously been reported. Methods. The measurements were carried out using high-spectral-resolution spectropolarimetric observations obtained with the High Accuracy Radial velocity Planet Searcher (HARPS) in polarimetric mode, installed at the ESO La Silla 3.6 m telescope. Results. For five He-rich stars, the longitudinal magnetic field was detected for the first time. For one target, HD 58260, the presence of a longitudinal magnetic field of the order of 1.8 kG has already been reported in the literature, but the magnetic field has remained constant over tens of years. Our measurement carried out using the polarimetric spectra obtained in 2015 March indicates a slight decrease of the longitudinal magnetic field strength compared to measurements reported in previous works. A search for periodic modulation in available photometric data allowed us to confidently establish a period of 2.64119 ± 0.00420 d in archival ASAS3 data for CPD–27°1791. No period could be determined for the other five stars. Conclusions. The obtained results support the scenario that all He-rich stars are detectably magnetic and form an extension of the Ap star phenomenon to higher temperatures.

scholarly journals Structure in the gas and magnetic field in S106

1991 ◽  
Vol 147 ◽  
pp. 61-64
Author(s):  
Richard M. Crutcher
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Massive Star ◽  
Zeeman Effect ◽  
The Other ◽  
Molecular Line ◽  
Show Evidence ◽  
The Magnetic Field

BIMA molecular-line observations show evidence for an expanding molecular ring around IRS 4, a newly formed massive star at the center of the bipolar nebula S106. VLA observations of the Zeeman effect in the OH 1665 MHz line show that the magnetic field strength is about 1 mG and that it reverses direction from one lobe of the bipolar nebula to the other.

MAGNETICALLY INDUCED "DRY" WATER LIKE STRUCTURE OF ELECTRON GAS IN DENSE STELLAR MATTER IN THE PRESENCE OF AN ULTRA STRONG MAGNETIC FIELD

2002 ◽  
Vol 17 (32) ◽  
pp. 2147-2154 ◽  
Author(s):  
SUTAPA GHOSH ◽  
SOMENATH CHAKRABARTY
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Strong Magnetic Field ◽  
Electron Gas ◽  
Core Region ◽  
Landau Levels ◽  
Stellar Matter ◽  
The Core ◽  
Dry Water ◽  
The Magnetic Field

It is shown that electron gas in dense stellar matter exhibit super-fluid (frictionless) like property if the magnetic field strength is high enough to populate only the zeroth Landau levels, i.e. it is possible that at the core of a magnetar, the proton matter behaves like a superconductor, neutron matter behaves like a super-fluid and electron gas shows super-fluidity without superconductivity. Therefore, the core region as a whole of a magnetar may behave like a frictionless matter which is quite surprising.

scholarly journals Effects of strong magnetic field on the formation of wakes in thermal QCD

2021 ◽  
Vol 36 (06) ◽  
pp. 2150045
Author(s):  
Mujeeb Hasan ◽  
Binoy Krishna Patra
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Strong Magnetic Field ◽  
Finite Temperature ◽  
Fast Moving ◽  
The Other ◽  
Other Hand ◽  
Induced Charge Density ◽  
Induced Charge ◽  
The Magnetic Field

We have investigated how the wakes in the induced charge density and in the potential due to the passage of highly energetic partons through a thermal QCD medium get affected by the presence of strong magnetic field [Formula: see text]. For that purpose, we wish to analyze first the dielectric responses of the medium both in presence and absence of strong magnetic field. Therefore, we have revisited the general form for the gluon self-energy tensor at finite temperature and finite magnetic field and then calculate the relevant structure functions at finite temperature and strong magnetic field limit (SMF: [Formula: see text] as well as [Formula: see text], [Formula: see text] is the electric charge (mass) of [Formula: see text]th flavor). We found that for slow moving partons, the real part of dielectric function is not affected by the magnetic field whereas for fast moving partons, for small [Formula: see text], it becomes very large and approaches towards its counterpart at [Formula: see text], for large [Formula: see text]. On the other hand the imaginary part is decreased for both slow and fast moving partons, due to the fact that the imaginary contribution due to quark loop vanishes. With these ingredients, we found that the oscillation in the (scaled) induced charge density, due to the very fast partons becomes less pronounced in the presence of strong magnetic field whereas for smaller parton velocity, no significant change is observed. For the (scaled) wake potential along the motion of fast moving partons (which is of Lennard–Jones (LJ-)type), the depth of negative minimum in the backward region gets reduced drastically, resulting in the reduction of the amplitude of oscillation. On the other hand in the forward region, it remains as the screened Coulomb one, except the screening now becomes much stronger for higher parton velocity. Similarly for the wake potential transverse to the motion of partons in both forward and backward regions, the depth of LJ potential for fast moving partons gets decreased severely, but still retains the forward–backward symm etry. However, for lower parton velocity, the magnetic field does not affect it significantly.

scholarly journals Structure in the gas and magnetic field in S106

1991 ◽  
Vol 147 ◽  
pp. 61-64
Author(s):  
Richard M. Crutcher
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Massive Star ◽  
Zeeman Effect ◽  
The Other ◽  
Molecular Line ◽  
Show Evidence ◽  
The Magnetic Field

BIMA molecular-line observations show evidence for an expanding molecular ring around IRS 4, a newly formed massive star at the center of the bipolar nebula S106. VLA observations of the Zeeman effect in the OH 1665 MHz line show that the magnetic field strength is about 1 mG and that it reverses direction from one lobe of the bipolar nebula to the other.

Asymmetric reconnection at the bow shock

2020 ◽  
Author(s):  
Herbert Gunell ◽  
Maria Hamrin ◽  
Oleksandr Goncharov ◽  
Alexandre De Spiegeleer ◽  
Stephen Fuselier ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Plasma Flow ◽  
Bow Shock ◽  
The Other ◽  
Magnetospheric Multiscale ◽  
The Magnetic Field

<p>Can reconnection be triggered as a directional discontinuity (DD) crosses the bow shock? Here we present some unique observations of asymmetric reconnection at a quasi-perpendicular bow shock as an interplanetary DD is crossing it simultaneously with the Magnetospheric Multiscale (MMS) mission. The data show indications of ongoing reconnection at the bow shock southward of the spacecraft. The DD is also observed by several upstream spacecraft (ACE, WIND, Geotail, and THEMIS B) and one downstream in the magnetosheath (Cluster 4), but none of them resolve signatures of ongoing reconnection. We therefore suggest that reconnection was temporarily triggered as the DD was compressed by the shock. Bow shock reconnection is inevitably asymmetric with both the density and the magnetic field strength being higher on one side of the X-line (the magneosheath side) than on the other side where the plasma flow also is supersonic (the solar wind side). Asymmetric reconnection of the bow shock type has never been studied before, and the data discussed here are hence unique.</p>

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

scholarly journals Effect of Magnetic Field on the Forced Convective Heat Transfer of Water–Ethylene Glycol-Based Fe3O4 and Fe3O4–MWCNT Nanofluids

2021 ◽  
Vol 11 (10) ◽  
pp. 4683
Author(s):  
Areum Lee ◽  
Chinnasamy Veerakumar ◽  
Honghyun Cho
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Field Strength ◽  
Ethylene Glycol ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Hybrid Nanofluid ◽  
Forced Convective Heat Transfer ◽  
The Magnetic Field

This paper discusses the forced convective heat transfer characteristics of water–ethylene glycol (EG)-based Fe3O4 nanofluid and Fe3O4–MWCNT hybrid nanofluid under the effect of a magnetic field. The results indicated that the convective heat transfer coefficient of magnetic nanofluids increased with an increase in the strength of the magnetic field. When the magnetic field strength was varied from 0 to 750 G, the maximum convective heat transfer coefficients were observed for the 0.2 wt% Fe3O4 and 0.1 wt% Fe3O4–MWNCT nanofluids, and the improvements were approximately 2.78% and 3.23%, respectively. The average pressure drops for 0.2 wt% Fe3O4 and 0.2 wt% Fe3O4–MWNCT nanofluids increased by about 4.73% and 5.23%, respectively. Owing to the extensive aggregation of nanoparticles by the external magnetic field, the heat transfer coefficient of the 0.1 wt% Fe3O4–MWNCT hybrid nanofluid was 5% higher than that of the 0.2 wt% Fe3O4 nanofluid. Therefore, the convective heat transfer can be enhanced by the dispersion stability of the nanoparticles and optimization of the magnetic field strength.

scholarly journals The effects of magnetic field strength on the properties of wind generated from hot accretion flow

2018 ◽  
Vol 615 ◽  
pp. A35 ◽  
Author(s):  
De-Fu Bu ◽  
Amin Mosallanezhad
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Pressure Gradient ◽  
Magnetic Field Strength ◽  
Magnetic Pressure ◽  
Gas Pressure ◽  
Accretion Flow ◽  
Accretion Flows ◽  
Black Hole Accretion ◽  
The Magnetic Field

Context. Observations indicate that wind can be generated in hot accretion flow. Wind generated from weakly magnetized accretion flow has been studied. However, the properties of wind generated from strongly magnetized hot accretion flow have not been studied. Aims. In this paper, we study the properties of wind generated from both weakly and strongly magnetized accretion flow. We focus on how the magnetic field strength affects the wind properties. Methods. We solve steady-state two-dimensional magnetohydrodynamic equations of black hole accretion in the presence of a largescale magnetic field. We assume self-similarity in radial direction. The magnetic field is assumed to be evenly symmetric with the equatorial plane. Results. We find that wind exists in both weakly and strongly magnetized accretion flows. When the magnetic field is weak (magnetic pressure is more than two orders of magnitude smaller than gas pressure), wind is driven by gas pressure gradient and centrifugal forces. When the magnetic field is strong (magnetic pressure is slightly smaller than gas pressure), wind is driven by gas pressure gradient and magnetic pressure gradient forces. The power of wind in the strongly magnetized case is just slightly larger than that in the weakly magnetized case. The power of wind lies in a range PW ~ 10−4–10−3 Ṁinc2, with Ṁin and c being mass inflow rate and speed of light, respectively. The possible role of wind in active galactic nuclei feedback is briefly discussed.

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