scholarly journals Initial observations of low-energy electrons in the Earth's magnetosphere with OGO 3

1967 ◽  
Vol 72 (1) ◽  
pp. 185 ◽  
Author(s):  
L. A. Frank
Keyword(s):  
Low Energy ◽  
Earth’S Magnetosphere ◽  
Low Energy Electrons ◽  
Earth's Magnetosphere

scholarly journals Charge-Exchange Byproduct Cold Protons in the Earth’s Magnetosphere

2022 ◽  
Vol 8 ◽  
Author(s):  
Joseph E. Borovsky ◽  
Jianghuai Liu ◽  
Raluca Ilie ◽  
Michael W. Liemohn
Keyword(s):  
Production Rate ◽  
Charge Exchange ◽  
Plasma Sheet ◽  
Impact Ionization ◽  
Neutral Hydrogen ◽  
Early Time ◽  
Low Energy ◽  
Geosynchronous Orbit ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

Owing to the spatial overlap of the ion plasma sheet (ring current) with the Earth’s neutral-hydrogen geocorona, there is a significant rate of occurrence of charge-exchange collisions in the dipolar portion of the Earth’s magnetosphere. During a charge-exchange collision between an energetic proton and a low-energy hydrogen atom, a low-energy proton is produced. These “byproduct” cold protons are trapped in the Earth’s magnetic field where they advect via E×B drift. In this report, the number density and behavior of this cold-proton population are assessed. Estimates of the rate of production of byproduct cold protons from charge exchange are in the vicinity of 1.14 cm−3 per day at geosynchronous orbit or about 5 tons per day for the entire dipolar magnetosphere. The production rate of cold protons owing to electron-impact ionization of the geocorona by the electron plasma sheet at geosynchronous orbit is about 12% of the charge-exchange production rate, but the production rate by solar photoionization of the neutral geocorona is comparable or larger than the charge-exchange production rate. The byproduct-ion production rates are smaller than observed early time refilling rates for the outer plasmasphere. Numerical simulations of the production and transport of cold charge-exchange byproduct protons find that they have very low densities on the nightside of geosynchronous orbit, and they can have densities of 0.2–0.3 cm−3 at geosynchronous orbit on the dayside. These dayside byproduct-proton densities might play a role in shortening the early phase of plasmaspheric refilling.

scholarly journals Low-energy neutral atoms in the Earth's magnetosphere: modeling

1992 ◽  
Author(s):  
Kurt R. Moore ◽  
David J. McComas ◽  
Herbert O. Funsten III ◽  
Michelle F. Thomsen
Keyword(s):  
Low Energy ◽  
Neutral Atoms ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

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