Schwingung eines Plasmazylinders in einem axialen Magnetfeld II

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.

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PHOTON-PAIR CONVERSION INTO NEUTRINOS IN A STRONG MAGNETIC FIELD

Modern Physics Letters A ◽

10.1142/s021773230100487x ◽

2001 ◽

Vol 16 (25) ◽

pp. 1659-1665 ◽

Cited By ~ 3

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.

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833171 ◽

2018 ◽

Vol 618 ◽

pp. L2 ◽

Cited By ~ 2

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.

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Structure in the gas and magnetic field in S106

Symposium - International Astronomical Union ◽

10.1017/s0074180900198778 ◽

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.

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Plasmonics NanoSensor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.74.13 ◽

2009 ◽

Vol 74 ◽

pp. 13-16

Author(s):

E.H. Khoo ◽

Ping Bai ◽

M.X. Gu ◽

H.S. Chu ◽

W.B. Ewe ◽

...

Keyword(s):

Magnetic Field ◽

Refractive Index ◽

Electromagnetic Wave ◽

External Magnetic Field ◽

Field Distribution ◽

The Third ◽

First Case ◽

Resonance Frequencies ◽

Electron Holes ◽

Metallic Waveguide

This paper presents a number of plasmonics based nanosensors that is currently being investigated in IHPC. In the first case, the influence of external magnetic field and electron on the field distribution of active semiconductor microcavity with elliptical shape is studied. It is observed that high amount of electron pumped into the elliptical microcavity demonstrate the plasmonics field distribution, which can be used to sense the change in wavelength and electron/holes densities. The second case will discuss about using plasmonics to enhance the electromagnetic wave from metallic waveguide slot. The enhancement is more than 100 times and this is important for the generation of electron-holes pair in PIN based photo-detector. The third case will discuss using the metallic nanowire to sense different surrounding materials. The small differences in the refractive index of the surrounding materials show the different plasmonics resonance frequencies.

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SPIN–LATTICE INTERACTION EXPERIMENTS ON COLOR CENTERS IN QUARTZ

Canadian Journal of Physics ◽

10.1139/p64-056 ◽

1964 ◽

Vol 42 (4) ◽

pp. 595-607 ◽

Cited By ~ 37

Author(s):

A. L. Taylor ◽

G. W. Farnell

Keyword(s):

Magnetic Field ◽

Dielectric Loss ◽

Low Frequency ◽

The Other ◽

Color Centers ◽

Resonance Signal ◽

Spin Lattice ◽

Resonance Frequencies ◽

Spin Resonance ◽

The Magnetic Field

The paramagnetism of the color centers in smoky quartz is caused by the electron which is missing from a nonbonding oxygen orbital near an aluminum impurity. The effects produced by externally introduced microwave phonons on the spin-resonance signal from these color centers have been studied in detail as a function of the relative phonon and spin-resonance frequencies, the phonon power, the spectrometer power, the magnetic field angle, and the phonon polarization. As has been noted previously, these interactions do not conform with those observed in other paramagnetic crystals. Effects of an applied electric field on the resonance lines and various further experiments on the color centers in smoky quartz are reported; two in particular suggest that the "hole", the missing electron, makes thermally excited transitions between two different sites adjacent to a given impurity atom. One of the experiments is a measurement of the cross relaxation which takes place between the various lines of the spectrum, while the other is a measurement of the low-frequency dielectric loss found at liquid helium temperatures. An attempt is made to discuss the spin-phonon results in terms of such transitions for the holes.

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Melt motion in a Czochralski crystal puller with an axial magnetic field: isothermal motion

Journal of Fluid Mechanics ◽

10.1017/s0022112086002549 ◽

1986 ◽

Vol 164 ◽

pp. 237-273 ◽

Cited By ~ 74

Author(s):

L. N. Hjellming ◽

J. S. Walker

Keyword(s):

Magnetic Field ◽

Electrical Conductivity ◽

Crystal Growth ◽

Field Strength ◽

Axial Magnetic Field ◽

Molten Silicon ◽

Crystal Face ◽

Rotation Rates ◽

Crucible Rotation ◽

The Magnetic Field

A magnetic field suppresses turbulence and thermal convection in a Czochralski crystal puller. The amounts and distributions of dopants and oxygen in the crystal are determined by the motion of the molten silicon during crystal growth. This paper presents analytical solutions for the melt motion in a Czochralski puller with a strong, uniform, axial magnetic field. The relatively small electrical conductivity of the crystal plays a key role in determining the flow. Certain combinations of crystal and crucible rotation rates lead to flow patterns with a large volume of almost stagnant fluid under most of the crystal face. The values of these rotation rates depend on the magnetic field strength.

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Structure in the gas and magnetic field in S106

Symposium - International Astronomical Union ◽

10.1017/s0074180900239399 ◽

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

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Forced Convection During Liquid Encapsulated Crystal Growth With an Axial Magnetic Field

Journal of Fluids Engineering ◽

10.1115/1.2820749 ◽

1998 ◽

Vol 120 (4) ◽

pp. 844-850 ◽

Cited By ~ 9

Author(s):

Nancy Ma ◽

John Walker ◽

David Bliss ◽

George Bryant

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Forced Convection ◽

Magnetic Field Strength ◽

Axial Magnetic Field ◽

Vertical Wall ◽

Czochralski Growth ◽

Centripetal Acceleration ◽

Radial Gap ◽

The Magnetic Field

This paper treats the forced convection, which is produced by the rotation of the crystal about its vertical centerline during the liquid-encapsulated Czochralski or Kyropoulos growth of compound semiconductor crystals, with a uniform vertical magnetic field. The model assumes that the magnetic field strength is sufficiently large that convective heat transfer and all inertial effects except the centripetal acceleration are negligible. With the liquid encapsulant in the radial gap between the outside surface of the crystal and the vertical wall of the crucible, the forced convection is fundamentally different from that with a free surface between the crystal and crucible for the Czochralski growth of silicon crystals. Again unlike the case for silicon growth, the forced convection for the actual nonzero electrical conductivity of an indium-phosphide crystal is virtually identical to that for an electrically insulating crystal. The electromagnetic damping of the forced convection is stronger than that of the buoyant convection. In order to maintain a given balance between the forced and buoyant convections, the angular velocity of the crystal must be increased as the magnetic field strength is increased.

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PARTICLE DYNAMICS OF STRUCTURE FORMATION AND DISINTEGRATION IN A MODEL MAGNETORHEOLOGICAL FLUID

International Journal of Modern Physics B ◽

10.1142/s0217979202012293 ◽

2002 ◽

Vol 16 (17n18) ◽

pp. 2314-2320 ◽

Cited By ~ 2

Author(s):

S. CUTILLAS ◽

J. LIU

Keyword(s):

Magnetic Field ◽

Refractive Index ◽

Correlation Function ◽

Field Strength ◽

Structure Formation ◽

Magnetorheological Fluid ◽

Particle Dynamics ◽

Diffusing Wave Spectroscopy ◽

Induced Structure ◽

The Magnetic Field

Using diffusing-wave spectroscopy (DWS), we studied experimentally the particle dynamics for a density matched superparamagnetic polystyrene colloid in a refractive index nearly matched multiple-layered cell. Particle dynamics is probed during structure formation and disintegration, when a 0.2 Hz square-wave magnetic field was turned on for 4 s and off for 1 s. The correlation function shows that the particles move slower and more restricted when the magnetic field is on. Even during the off cycle of the magnetic field, the particles' motion is not free but still constrained with a less degree than that when the field is on. Thus, it takes more than 1 s for the induced structure to disintegrate. As the magnetic field strength increases, so does the degree of constrain for both the on and off cycle of the magnetic field and the differences between them. Modified telegrapher theory is found to be valid for our strongly absorbing and limited multiple scattering sample.

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Flow behavior of cementitious-like suspension with nano-Fe3O4 particles under external magnetic field

Materials and Structures ◽

10.1617/s11527-021-01801-y ◽

2021 ◽

Vol 54 (6) ◽

Author(s):

Dengwu Jiao ◽

Karel Lesage ◽

Mert Yücel Yardimci ◽

Caijun Shi ◽

Geert De Schutter

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

High Magnetic Field ◽

Apparent Viscosity ◽

Flow Behavior ◽

Limestone Powder ◽

Powder Suspension ◽

The Magnetic Field

AbstractThe flow behavior of cementitious-like (limestone powder) suspension containing nano-Fe3O4 particles at constant shear rate of 10 s−1, characterized by the evolution of apparent viscosity over time, is investigated under various magnetic fields. Results show that the limestone powder suspension at flow-state exhibits remarkable magneto-rheological responses, reflected by a significant increase in the apparent viscosity after applying an external magnetic field. A higher field strength corresponds to a more rapid and pronounced response. The apparent viscosity experiences a sudden alteration with the stepwise change of the magnetic field due to the formation or disintegration of magnetic clusters. Linearly increasing magnetic field strength at low ranges (e.g. 0 T–0.3 T) shows less influences on the evolution of apparent viscosity, while at relatively high magnetic field, the apparent viscosity gradually increases with the magnetic field strength and the increase rate is comparable to that obtained under constant high magnetic field of 0.75 T. When the magnetic field is removed, the apparent viscosity exhibits a sharp reduction. If the magnetic field strength linearly decreases to zero, however, the apparent viscosity continuously increases until reaching a peak and then gradually decreases. This research shows in different ways how a desired apparent viscosity level of a cementitious-like suspension can be reached by means of an external magnetic field.

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