Energetic electrons and ions in the magnetosheath at low and medium latitudes: Prognoz 10 data

Recent progress and future prospects in diagnostics of energetic electrons and ions in the flares are reviewed, together with the roles they play in the flare as a whole. Most of the discussion centres on hard X-ray and gamma-ray and thermal plasma emission data, rather than on radio sources. Since Solar Maximum Mission and Hinotori there has been major progress in all areas of flare electron diagnostics. Electron spectra are now recoverable with some precision, electrons with energies above 10 MeV are known to be highly anisotropic, and indications are available of the spatial distribution of electrons at 20 keV. Timescales of electron acceleration are now known to be shorter than 0.1 s. Energetic electrons are believed to carry much of the flare power. Ion diagnostics are more limited. For greater than 1 MeV ions the flux, spectrum and acceleration timescale are now quite well known. Low energy ions are hard to diagnose but have been invoked as a flare heating mechanism alternative to electron beams. The problems with beam heating models are discussed with special attention to the problems of the low energy proton model and its only direct diagnostic, Hα impact polarization. Finally, theoretical problems associated with return currents and with accelerator requirements are discussed and attention is drawn to the possible importance of entropy as well as energy considerations.

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Simultaneous observation of upward moving field-aligned energetic electrons and ions on auroral zone field lines

Journal of Geophysical Research Atmospheres ◽

10.1029/ja093ia09p09765 ◽

1988 ◽

Vol 93 (A9) ◽

pp. 9765 ◽

Cited By ~ 106

Author(s):

B. Hultqvist ◽

R. Lundin ◽

K. Stasiewicz ◽

L. Block ◽

P.-A. Lindqvist ◽

...

Keyword(s):

Auroral Zone ◽

Simultaneous Observation ◽

Energetic Electrons ◽

Electrons And Ions ◽

Field Lines ◽

Upward Moving ◽

Zone Field

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A compact design for velocity-map imaging of energetic electrons and ions

The Journal of Chemical Physics ◽

10.1063/1.4984076 ◽

2017 ◽

Vol 147 (1) ◽

pp. 013942 ◽

Cited By ~ 1

Author(s):

D. Schomas ◽

N. Rendler ◽

J. Krull ◽

R. Richter ◽

M. Mudrich

Keyword(s):

Velocity Map Imaging ◽

Energetic Electrons ◽

Electrons And Ions ◽

Compact Design

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In situ irradiation effects studies in medium- and high-voltage TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137549 ◽

1995 ◽

Vol 53 ◽

pp. 234-235

Author(s):

Charles W. Allen

Keyword(s):

Cross Section ◽

Particle Flux ◽

Threshold Value ◽

High Energy ◽

Irradiation Damage ◽

Defect Complexes ◽

Lattice Position ◽

Electrons And Ions ◽

The Masses

With respect to structural consequences within a material, energetic electrons, above a threshold value of energy characteristic of a particular material, produce vacancy-interstial pairs (Frenkel pairs) by displacement of individual atoms, as illustrated for several materials in Table 1. Ion projectiles produce cascades of Frenkel pairs. Such displacement cascades result from high energy primary knock-on atoms which produce many secondary defects. These defects rearrange to form a variety of defect complexes on the time scale of tens of picoseconds following the primary displacement. A convenient measure of the extent of irradiation damage, both for electrons and ions, is the number of displacements per atom (dpa). 1 dpa means, on average, each atom in the irradiated region of material has been displaced once from its original lattice position. Displacement rate (dpa/s) is proportional to particle flux (cm-2s-1), the proportionality factor being the “displacement cross-section” σD (cm2). The cross-section σD depends mainly on the masses of target and projectile and on the kinetic energy of the projectile particle.

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The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117777 ◽

1985 ◽

Vol 43 ◽

pp. 154-157

Author(s):

A.J. Tousimis

Keyword(s):

Ion Beam ◽

Depth Resolution ◽

Sample Surface ◽

High Energy ◽

X Rays ◽

X Ray ◽

Electrons And Ions ◽

Spatial Depth ◽

Minimum Surface Area ◽

Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

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Detector strategies for environmental scanning electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131115 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1296-1297

Author(s):

Klaus-Ruediger Peters

Keyword(s):

High Vacuum ◽

Environmental Scanning Electron Microscopy ◽

Charge Carriers ◽

Environmental Scanning ◽

Surface Information ◽

X Ray ◽

Detector Electrode ◽

Electrons And Ions ◽

Low Energy Electrons ◽

Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

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