A micromagnetic study of the influences of electric currents and magnetic fields on the Spin-Cherenkov effect

2016 ◽  
Vol 481 ◽  
pp. 59-62 ◽  
Author(s):  
Jie Chen ◽  
Hong Xia ◽  
Xiaoyan Zeng ◽  
Ming Yan
Keyword(s):  
Magnetic Fields ◽  
Electric Currents ◽  
Cherenkov Effect

A Case for Magneto Hydro Dynamics (MHD)

2001 ◽  
Author(s):  
Haim H. Bau
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Lorentz Force ◽  
Electric Fields ◽  
Biological Fluids ◽  
Fluid Volume ◽  
Chaotic Advection ◽  
Complex Flows ◽  
Electric Currents

Abstract In this paper, I review some of our work on the use of magneto hydrodynamics (MHD) for pumping, controlling, and stirring fluids in microdevices. In many applications, one operates with liquids that are at least slightly conductive such as biological fluids. By patterning electrodes inside flow conduits and subjecting these electrodes to potential differences, one can induce electric currents in the liquid. In the presence of a magnetic field, a Lorentz force is generated in a direction that is perpendicular to both the magnetic and electric fields. Since one has a great amount of freedom in patterning the electrodes, one can induce forces in various directions so as to generate complex flows including “guided” flows in virtual, wall-less channels. The magnetic flux generators can be either embedded in the device or be external. Despite their unfavorable scaling (the magnitude of the forces is proportional to the fluid volume), MHD offers many advantages such as the flexibility of applying forces in any desired direction and the ability to adjust the magnitude of the forces by adjusting either the electric and/or magnetic fields. We provide examples of (i) MHD pumps; (ii) controlled networks of conduits in which each conduit is equipped with a MHD actuator and by controlling the voltage applied to each actuator, one can direct the liquid to flow in any desired way without a need for valves; and (iii) MHD stirrers including stirrers that exhibit chaotic advection.

Introduction

2017 ◽  
pp. 3-12
Author(s):  
Riitta Hari ◽  
Aina Puce
Keyword(s):  
Magnetic Fields ◽  
Human Brain ◽  
Brain Dynamics ◽  
Electric Currents ◽  
Electrical Currents ◽  
Activation Patterns ◽  
Neuronal Communication ◽  
Electrical Potentials ◽  
Electric And Magnetic Fields ◽  
The Brain

Neuronal communication in the brain is associated with minute electrical currents that give rise to both electrical potentials on the scalp (measurable by means of electroencephalography [EEG]) and magnetic fields outside the head (measurable by magnetoencephalography [MEG]). Both MEG and EEG are noninvasive neurophysiological methods used to study brain dynamics, that is temporal changes in the activation patterns, and sequences in signal progression. Differences between MEG and EEG mainly reflect differences in the spread of electric and magnetic fields generated by the same electric currents in the human brain. This chapter provides an overall description of the main principles of MEG and EEG and provides background for the following chapters in this and subsequent sections.

scholarly journals Flows, Evolution of Magnetic Fields, and Flares

1993 ◽  
Vol 141 ◽  
pp. 323-332 ◽  
Author(s):  
Haimin Wang
Keyword(s):  
Magnetic Fields ◽  
Magnetic Structure ◽  
Solar Flares ◽  
Active Regions ◽  
Magnetic Polarity ◽  
Flux Emergence ◽  
Electric Currents ◽  
Magnetic Shear ◽  
Before And After

AbstractThis paper reviews observations on the evolution of magnetic fields and flows in active regions which produce major flares. It includes the following topics: (1) Relationship between magnetic shear and flares; (2) Relationship between electric currents and flares; (3) Flows in active regions, particularly the emergence of new flux inside sheared penumbrae, and the mixed magnetic polarity nature of this kind of flux emergence; and (4) Changes of magnetic structure immediately before and after major solar flares; in particular, I will describe some recent findings that shear may increase after major flares.

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