Motion of an Electron in the Field of a Magnetic Pole

1984 ◽  
pp. 217-221
Author(s):  
Harish-Chandra
Keyword(s):  
Magnetic Pole

A Magnetic Spectrometer for a Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 436-437
Author(s):  
A. Kosiara ◽  
J. W. Wiggins ◽  
M. Beer
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Magnetic Spectrometer ◽  
Fringe Field ◽  
Curvature Radius ◽  
Magnetic Pole ◽  
Quadrupole Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Under Construction ◽  
Image Position

A magnetic spectrometer to be attached to the Johns Hopkins S. T. E. M. is under construction. Its main purpose will be to investigate electron interactions with biological molecules in the energy range of 40 KeV to 100 KeV. The spectrometer is of the type described by Kerwin and by Crewe Its magnetic pole boundary is given by the equationwhere R is the electron curvature radius. In our case, R = 15 cm. The electron beam will be deflected by an angle of 90°. The distance between the electron source and the pole boundary will be 30 cm. A linear fringe field will be generated by a quadrupole field arrangement. This is accomplished by a grounded mirror plate and a 45° taper of the magnetic pole.

scholarly journals Circumstellar environment of 55 Cancri

2020 ◽  
Vol 633 ◽  
pp. A48 ◽  
Author(s):  
C. P. Folsom ◽  
D. Ó Fionnagáin ◽  
L. Fossati ◽  
A. A. Vidotto ◽  
C. Moutou ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stellar Wind ◽  
Large Scale ◽  
Rotation Axis ◽  
Doppler Imaging ◽  
Magnetic Pole ◽  
Average Strength ◽  
Detailed Understanding ◽  
The Magnetic Field ◽  
Circumstellar Environment

Context. 55 Cancri hosts five known exoplanets, most notably the hot super-Earth 55 Cnc e, which is one of the hottest known transiting super-Earths. Aims. Because of the short orbital separation and host star brightness, 55 Cnc e provides one of the best opportunities for studying star-planet interactions (SPIs). We aim to understand possible SPIs in this system, which requires a detailed understanding of the stellar magnetic field and wind impinging on the planet. Methods. Using spectropolarimetric observations and Zeeman Doppler Imaging, we derived a map of the large-scale stellar magnetic field. We then simulated the stellar wind starting from the magnetic field map, using a 3D magneto-hydrodynamic model. Results. The map of the large-scale stellar magnetic field we derive has an average strength of 3.4 G. The field has a mostly dipolar geometry; the dipole is tilted by 90° with respect to the rotation axis and the dipolar strength is 5.8 G at the magnetic pole. The wind simulations based on this magnetic geometry lead us to conclude that 55 Cnc e orbits inside the Alfvén surface of the stellar wind, implying that effects from the planet on the wind can propagate back to the stellar surface and result in SPI.

Feasibility Study of a MEMS Viscous Rotary Engine Power System (VREPS)

2004 ◽  
Author(s):  
Thomas H. Cauley ◽  
Jose D. Rosario-Rosario ◽  
Albert P. Pisano
Keyword(s):  
Power System ◽  
Permanent Magnet ◽  
Electrical Power ◽  
Rotating Disk ◽  
Creeping Flow ◽  
Magnetic Pole ◽  
Rotary Engine ◽  
Magnetic Circuits ◽  
Isentropic Efficiency ◽  
Engine Power

In this paper is presented an analytic, theoretical and numerical study of the Viscous Rotary Engine Power System (VREPS). In addition, a proposed process flow for the fabrication of the VREPS using DRIE of silicon is described. The design premise of the VREPS is to derive mechanical power from the surface viscous shearing forces developed by a pressure driven flow present between a rotating disk or annulus and a stationary housing. The resulting motion of the rotating disk or annulus is converted into electrical power by using an external permanent magnet, embedded nickel-iron magnetic circuits, and an external switched magnetic pole electric generator similar to the design proposed by M. Senesky for the UC Berkeley micro-Wankel Engine [1]. This paper will examine the power output, isentropic efficiency, and operating characteristics of the disk and annular viscous turbines using the lubrication approximation and the Creeping Flow Equations (Stokes Flow). The viscous turbine is optimized for maximum isentropic efficiency using MATLAB numerical optimization routines. Finally, a unique triple-wafer micro-fabrication process for VREPS is presented. The proposed design consists of a 250 μm thick, 3.4 mm OD / 2.4 mm ID annular rotor with embedded magnetic poles and four 10 μm driving channels on each side of the rotor. Electrical power is generated with a switched magnetic pole generator, external permanent magnet, and integrated magnetic circuits. Calculations with water predict an output power of 825 mW at an isentropic efficiency of 25% using a pressure drop of 5 MPa cross the device.

Application of Magnetoelastic Effect of Ferromagnetic Material in Stress Measurement

2012 ◽  
Vol 496 ◽  
pp. 306-309 ◽  
Author(s):  
Yan Ping Shi ◽  
Shu Hua Fan
Keyword(s):  
Mathematical Model ◽  
Stress Measurement ◽  
Ferromagnetic Material ◽  
Induced Voltage ◽  
Practical Application ◽  
Magnetic Pole ◽  
Magnetoelastic Effect ◽  
Voltage Output ◽  
Contact Sensor ◽  
Test Result

A new non-contact sensor with three magnetic pole based on magnetoelastic effect was designed, and its operation principle and mathematical model of induced voltage output were given. The output characteristic of the sensor affected by field current intensity, frequency, and the gap between the probe of the sensor and the surface of the material tested was analyzed by testing. The calculation result based on the output model found by the paper accord basically with the test result. The results of the test have showed that the measuring precision and sensitivity of the sensor can meet the demands of the general practical application.

scholarly journals Expedition to the North Magnetic Pole

1902 ◽  
Vol 20 (6) ◽  
pp. 627
Author(s):  
Roald Amundsen
Keyword(s):  
Magnetic Pole ◽  
The North ◽  
North Magnetic Pole

scholarly journals Northern preference for terrestrial electromagnetic energy input from space weather

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
I. P. Pakhotin ◽  
I. R. Mann ◽  
K. Xie ◽  
J. K. Burchill ◽  
D. J. Knudsen
Keyword(s):  
Space Weather ◽  
Energy Input ◽  
Rotation Axis ◽  
Electromagnetic Energy ◽  
Magnetic Pole ◽  
Poynting Flux ◽  
Auroral Emissions ◽  
Energy And Momentum ◽  
Swarm Satellite ◽  
Northern And Southern Hemispheres

AbstractTerrestrial space weather involves the transfer of energy and momentum from the solar wind into geospace. Despite recently discovered seasonal asymmetries between auroral forms and the intensity of emissions between northern and southern hemispheres, seasonally averaged energy input into the ionosphere is still generally considered to be symmetric. Here we show, using Swarm satellite data, a preference for electromagnetic energy input at 450 km altitude into the northern hemisphere, on both the dayside and the nightside, when averaged over season. We propose that this is explained by the offset of the magnetic dipole away from Earth’s center. This introduces a larger separation between the magnetic pole and rotation axis in the south, creating different relative solar illumination of northern and southern auroral zones, resulting in changes to the strength of reflection of incident Alfvén waves from the ionosphere. Our study reveals an important asymmetry in seasonally averaged electromagnetic energy input to the atmosphere. Based on observed lower Poynting flux on the nightside this asymmetry may also exist for auroral emissions. Similar offsets may drive asymmetric energy input, and potentially aurora, on other planets.

Sign in / Sign up

Export Citation Format

Share Document