scholarly journals Fisher analysis on wide-band polarimetry for probing the intergalactic magnetic field

2014 ◽  
Vol 66 (1) ◽  
pp. 5 ◽  
Author(s):  
Shinsuke Ideguchi ◽  
Keitaro Takahashi ◽  
Takuya Akahori ◽  
Kohei Kumazaki ◽  
Dongsu Ryu
Keyword(s):  
Magnetic Field ◽  
Wide Band ◽  
Intergalactic Magnetic Field

scholarly journals Induced Magnetic Field-Based Indoor Positioning System for Underwater Environments

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2218
Author(s):  
Sizhen Bian ◽  
Peter Hevesi ◽  
Leif Christensen ◽  
Paul Lukowicz
Keyword(s):  
Magnetic Field ◽  
Low Cost ◽  
Autonomous Underwater Vehicles ◽  
Wide Band ◽  
Propagation Delay ◽  
Positioning System ◽  
Indoor Environments ◽  
Coverage Area ◽  
Underwater Positioning ◽  
Similar Accuracy

Autonomous underwater vehicles (AUV) are seen as an emerging technology for maritime exploration but are still restricted by the availability of short range, accurate positioning methods necessary, e.g., when docking remote assets. Typical techniques used for high-accuracy positioning in indoor use case scenarios, such as systems using ultra-wide band radio signals (UWB), cannot be applied for underwater positioning because of the quick absorption of the positioning medium caused by the water. Acoustic and optic solutions for underwater positioning also face known problems, such as the multi-path effects, high propagation delay (acoustics), and environmental dependency. This paper presents an oscillating magnetic field-based indoor and underwater positioning system. Unlike those radio wave-based positioning modalities, the magnetic approach generates a bubble-formed magnetic field that will not be deformed by the environmental variation because of the very similar permeability of water and air. The proposed system achieves an underwater positioning mean accuracy of 13.3 cm in 2D and 19.0 cm in 3D with the multi-lateration positioning method and concludes the potential of the magnetic field-based positioning technique for underwater applications. A similar accuracy was also achieved for various indoor environments that were used to test the influence of cluttered environment and of cross environment. The low cost and power consumption system is scalable for extensive coverage area and could plug-and-play without pre-calibration.

scholarly journals Impact of Plasma Instability on Constraint of the Intergalactic Magnetic Field

2018 ◽  
Vol 870 (1) ◽  
pp. 17 ◽  
Author(s):  
Dahai Yan ◽  
Jianeng Zhou ◽  
Pengfei Zhang ◽  
Qianqian Zhu ◽  
Jiancheng Wang
Keyword(s):  
Magnetic Field ◽  
Plasma Instability ◽  
Intergalactic Magnetic Field

Development and Design of the Dynamic Vibration Absorber Using Magneto-Rheological Elastomer for the Weight and Power Consumption Saving

2019 ◽  
Author(s):  
Osamu Terashima ◽  
Mika Nakata ◽  
Toshihiko Komatsuzaki
Keyword(s):  
Magnetic Field ◽  
Power Consumption ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Wide Band ◽  
Test Results ◽  
Dynamic Vibration Absorber ◽  
Small Power ◽  
Dynamic Absorber ◽  
Magneto Rheological

Abstract In this study, a broadband frequency tunable dynamic absorber was designed and fabricated based on the primary design principle of a mass damper. A magneto-rheological elastomer that can change the relative stiffness when an external magnetic field is applied was used to control the natural frequency of the movable mass of the absorber. A coil to generate the magnetic field was also used as a movable mass to decrease the total weight and to create a constant closed loop of the magnetic force. The hammer impact test results show that the present absorber could change its natural frequency with minimal electric power and had a constant damping ratio. Experimental results of vibration absorbing of an acrylic flat plate show that the proposed absorber could change the natural frequency of the movable mass and reduce the vibration over a wide band by constantly applying the optimum current to the coil in the device with a small power consumption (less than 10 W). Therefore, the proposed absorber works effectively. Further, a technique to determine the electric current applied to the coil automatically based on the phase difference of the vibrational acceleration of the movable mass and the vibrating objective was also presented.

The Behavior of the Ferromagnet/Wide-Band Polymer Heterostructure in Magnetic Field

2012 ◽  
Vol 190 ◽  
pp. 149-152 ◽  
Author(s):  
Natalya V. Vorob’eva ◽  
Aleksei N. Lachinov ◽  
V.M. Kornilov
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Polymer Film ◽  
Spin Transport ◽  
Wide Band ◽  
Experimental Results ◽  
Spin Polarized ◽  
Conductive State

The experimental results for huge magnetoresistance in polymer/ferromagnet system have been considered. The evidences have been established for the relation of the partially spin-polarized current in the structure and the magnetoresistance events. The model of charge and spin transport of the high-conductive state of wide-band polymer film/ferromagnet heterostructure have been proposed on the base of the experimental data totality.

scholarly journals Prospect on intergalactic magnetic field measurements with gamma-ray instruments

2012 ◽  
Vol 8 (S294) ◽  
pp. 459-470
Author(s):  
Hélène Sol ◽  
Andreas Zech ◽  
Catherine Boisson ◽  
Henric Krawczynski ◽  
Lisa Fallon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
Field Measurements ◽  
High Energy ◽  
Wide Field ◽  
Extragalactic Background Light ◽  
Spatially Extended ◽  
Very High Energy ◽  
Energy Gamma ◽  
Intergalactic Magnetic Field

AbstractObserving high-energy gamma-rays from Active Galactic Nuclei (AGN) offers a unique potential to probe extremely tiny values of the intergalactic magnetic field (IGMF), a long standing question of astrophysics, astroparticle physics and cosmology. Very high energy (VHE) photons from blazars propagating along the line of sight interact with the extragalactic background light (EBL) and produce e+e− pairs. Through inverse-Compton interaction, mainly on the cosmic microwave background (CMB), these pairs generate secondary GeV-TeV components accompanying the primary VHE signal. Such secondary components would be detected in the gamma-ray range as delayed “pair echos” for very weak IGMF (B < 10−16G), while they should result in a spatially extended gamma-ray emission around the source for higher IGMF values (B > 10−16G). Coordinated observations with space (i.e. Fermi) and ground-based gamma-ray instruments, such as the present Cherenkov experiments H.E.S.S., MAGIC and VERITAS, the future Cherenkov Telescope Array (CTA) Observatory, and the wide-field detectors such as HAWC and LHAASO, should allow to analyze and finally detect such echos, extended emission or pair halos, and to further characterize the IGMF.

Sign in / Sign up

Export Citation Format

Share Document