scholarly journals MEASUREMENT OF THE TILT ANGLE OF THE SUNSPOT MAGNETIC FIELD AXIS (METHOD AND RESULTS)

2019 ◽  
Author(s):  
N.A. Topchilo ◽  
◽  
N.G. Peterova ◽  
Keyword(s):  
Magnetic Field ◽  
Tilt Angle ◽  
Magnetic Field Axis

Parameters controlling the substorm onset location

2021 ◽  
Author(s):  
Reham Elhawary ◽  
Karl Laundal ◽  
Jone Reistad ◽  
Anders Ohma ◽  
Spencer Hatch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Tilt Angle ◽  
Linear Regression Analysis ◽  
Substorm Onset ◽  
Azimuthal Component ◽  
Field Orientation ◽  
Hall Conductance ◽  
Onset Location ◽  
Dipole Tilt

<p>Substorm onset location varies over a range of magnetic local time (MLT) and magnetic latitudes (MLat). It is well known that about 5% of the variation in onset MLT can be explained by variations in interplanetary magnetic field orientation and dipole tilt angle. Both parameters introduce an azimuthal component in the magnetic field in the magnetosphere such that the projection of the onset MLT in the ionosphere is shifted. The MLT of the onset near the magnetopsheric equatorial plane is even less predictable. Recent studies have suggested that gradients in the ionospheric Hall conductance lead to a duskward shift of tail dynamics, which could also influence the location of substorm onset. Our goal is to test these ideas by quantifying the dependence of the spatial variation of the onset location on external and internal conditions. We focus on the correlation between the substorm onset location with conditions prior to the onset, such as the interplanetary magnetic field By component, dipole tilt angle, and estimates of the Hall conductance. Linear regression analysis is used to determine the substorm onset location dependence on the proposed variables.</p>

scholarly journals Radiation Beaming in Pulsars

1971 ◽  
Vol 46 ◽  
pp. 455-456
Author(s):  
V. Canuto
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Coming Out ◽  
Critical Magnetic Field ◽  
Zero Field ◽  
Ordinary Wave ◽  
Magnetic Field Axis ◽  
Field Lines ◽  
Star Surface ◽  
The Magnetic Field

It is usually considered that the beaming of the radiation coming out of a pulsar has to be strictly connected with the mechanism producing the radiation itself. We want to show that even when the emitting mechanism gives rise to an isotropically distributed radiation, the presence of a strong magnetic field will automatically beam the radiation preferentially along the magnetic field line rather than in any other direction. We have computed the Compton scattering and from that the opacity KH (K0 is the opacity for zero field). In Figure 1 the ratio KH/K0 is given vs. θ, the angle between the propagation vector and the magnetic field axis. Hq is a critical magnetic field numerically equal to 4.41 × 1013 G; Ne is the electron density. For the ordinary wave the opacity is reduced at θ = 0, while it is unaffected at θ = π/2 where KH → K0. Even at θ = π/4 the ratio KH/K0 is still ≃ 10−2, and a good beaming is still present. The values of the parameters are proper for a neutron star surface. It is to be noticed that the ratio KH/K0 is of the order of (ω/ωH)2 or [(kT/mc2)/(H/Hq]2. One therefore can conclude that the presence of a magnetic field itself assures the beaming of radiation along the field lines.

scholarly journals Comparative Study on Planetary Magnetosphere in the Solar System

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1673
Author(s):  
Ching-Ming Lai ◽  
Jean-Fu Kiang
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar System ◽  
Comparative Study ◽  
Magnetic Reconnection ◽  
Tilt Angle ◽  
Planetary Magnetosphere ◽  
Field Distributions ◽  
Mhd Simulations ◽  
The Magnetic Field

The magnetospheric responses to solar wind of Mercury, Earth, Jupiter and Uranus are compared via magnetohydrodynamic (MHD) simulations. The tilt angle of each planetary field and the polarity of solar wind are also considered. Magnetic reconnection is illustrated and explicated with the interaction between the magnetic field distributions of the solar wind and the magnetosphere.

scholarly journals Substorm onset location and dipole tilt angle

2006 ◽  
Vol 24 (2) ◽  
pp. 577-588 ◽  
Author(s):  
J. Wanliss
Keyword(s):  
Magnetic Field ◽  
Tilt Angle ◽  
Source Region ◽  
Radial Distance ◽  
Substorm Onset ◽  
Magnetospheric Substorms ◽  
Data Set ◽  
Current Disruption ◽  
Onset Location ◽  
Dipole Tilt

Abstract. From an initial data set of over 200 substorms we have studied a subset of 30 magnetospheric substorms close to magnetic midnight to investigate, in a statistical fashion, the source region of the auroral arc that brightens at the onset of expansive phase. This arc is usually identified as the ionospheric signature of the expansive phase onset that occurs in the magnetotail. All the substorm onsets were identified via ground-based magnetometer and photometer data from the CANOPUS array. Various Tsyganenko global magnetic field models were used to map magnetic field lines from the location of the onset arc out to its greatest radial distance in the magnetotail. The results appear to favour the current disruption model of substorms since the average onset location has an average of 14.1 Earth radii (RE) and is therefore more consistent with theories that place the onset location in the inner magnetotail. For the narrow range of tilts available our modeling indicates the parameter that appears to strongly influence the location of the substorm onset is the dipole tilt angle; as tilt becomes less negative onsets occur further downtail.

Magnetically Tailored Arc and Glow Discharge Plasmas for Atomic Spectroscopy

1987 ◽  
Vol 41 (5) ◽  
pp. 833-843 ◽  
Author(s):  
K. Trivedi ◽  
S. Tanguay ◽  
M. Matties ◽  
R. Sacks
Keyword(s):  
Magnetic Field ◽  
Glow Discharge ◽  
Vertical Displacement ◽  
Atomic Spectroscopy ◽  
Radiative Properties ◽  
Current Channel ◽  
Drift Motion ◽  
Magnetic Field Axis ◽  
Discharge Plasmas ◽  
The Magnetic Field

Three magnetic field-plasma configurations are used to study the interaction of external magnetic fields with analytically useful plasma devices. First, a magnetic field oscillating at 60 Hz and normal to the electric field in a 12-A direct current arc plasma is used to obtain an Ē×B̄ drift motion of the arc current channel. This causes a periodic vertical displacement of the channel. Second, a cw magnetic field is used to alter the structure and radiative properties of a demountable glow discharge lamp that uses a center-post cathode. The magnetic field axis is parallel to the cathode axis, and the lamp is operated in a pseudo-magnetron mode. Third, a damped, oscillatory magnetic field produced by discharging a capacitor through a coil is used to alter the radiative characteristics of several commercial hollow cathode lamps. The magnetic field is parallel to the cathode axis, and again the lamps operate in a pseudo-magnetron mode. In all three systems, the presence of the magnetic field drastically alters the radiative properties of the plasmas.

scholarly journals Research on a novel magnetic tilt sensor designed using Hall elements and ferrofluid

2019 ◽  
Vol 70 (5) ◽  
pp. 406-411
Author(s):  
Yavuz Öztürk ◽  
Ismail Yariçi
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Tilt Angle ◽  
Face To Face ◽  
Restoring Forces ◽  
Working Principle ◽  
Tilt Sensor ◽  
Hall Effect Sensors ◽  
Two Sides ◽  
The Magnetic Field

Abstract In this study, a simple, adjustable, bidirectional tilt sensor was designed using a pair of linear Hall effect sensors and magnets. Theoretical analysis and experimental results of the sensor system were presented. The working principle of the designed sensor is based on sensing the magnetic field of a mobile magnet which displaces with respect to the tilt angle. Two magnet sets were placed at the two ends of the system to apply repulsive restoring forces on the mobile magnet. The mobile magnet was coated with a light hydrocarbon based ferrofluid as a lubricant to reduce friction. Fixed Hall effect sensors were placed face to face at the two sides of the mobile magnet to monitor the magnetic field of the mobile magnet. It was shown that both experimentally and theoretically, it is possible to measure the approximate tilt angle linearly and quadratically by calculating the sum and difference of the Hall sensor voltages for the relatively small movements of the mobile magnet. Moreover, the system was also examined for the different sets of side magnets. For three different side magnet configurations, approximately 0.7, 1.1 and 1.68 V/rad sensitivity values were observed in the linear range.

scholarly journals Effect of Magnetic Field and Temperature on the Exchange Bias in Phase-Separated Nd1-xSrxCoO3(x=0.10, 0.15)

2015 ◽  
Vol 9 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Yi-Yun Yang
Keyword(s):  
Magnetic Field ◽  
Exchange Bias ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Freezing Temperature ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Magnetic Field Axis ◽  
Coexisting Phases ◽  
The Magnetic Field

The exchange bias phenomena of phase-separated Nd1-xSrxCoO3(x=0.10, 0.15) samples were systematically investigated in this paper. The samples were prepared using conventional solid state reaction method. When the NdSrCoO samples cooled down in magnetic field below freezing temperature, the hysteresis loops shifted along the magnetic field axis. Moreover, exchange bias of Nd1-xSrxCoO3 is strongly dependent on the field and the temperature. The influence of magnetic field on the relative ratio of the coexisting phases may be responsible for these behaviors. Therefore, our study confirmed that in phase-separated system, the exchange coupling at the interface between the ferromagnetism clusters and the spin glass regions may induce interfacial exchange anisotropy.

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