scholarly journals FAST observations of upward accelerated electron beams and the downward field-aligned current region

2000 ◽  
pp. 173-180 ◽  
Author(s):  
R. C. Elphic ◽  
J. Bonnell ◽  
R. J. Strangeway ◽  
C. W. Carlson ◽  
M. Temerin ◽  
...  
Keyword(s):  
Electron Beams ◽  
Current Region ◽  
Field Aligned Current

scholarly journals <i>Letter to the Editor</i> Low-frequency electric field fluctuations and field-aligned electron beams around the edge of an auroral acceleration region

2001 ◽  
Vol 19 (3) ◽  
pp. 389-393 ◽  
Author(s):  
W. Miyake ◽  
R. Yoshioka ◽  
A. Matsuoka ◽  
T. Mukai ◽  
T. Nagatsuma
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electron Beams ◽  
Low Frequency ◽  
Static Field ◽  
Acceleration Region ◽  
Auroral Acceleration Region ◽  
Field Fluctuations ◽  
Current Region ◽  
Frequency Electric Field

Abstract. Electron beams narrowly collimated to the magnetic field line were observed continuously from a down-ward current region to an auroral acceleration region (i.e., upward current region). They were well correlated with low-frequency electric field fluctuations in the auroral acceleration region as well as in the adjacent downward current region. Magnetic field fluctuations were found only in the downward current region. The analysis suggests that static field-aligned electric fields are not fully responsible for the filed-aligned electron acceleration; the ac electric field, presumably associated with Alfvenic fluctuations, should also be involved in the acceleration of ionospheric electrons.Key words. Ionosphere (particle acceleration) – Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions)

FAST observations in the downward auroral current region: Energetic upgoing electron beams, parallel potential drops, and ion heating

1998 ◽  
Vol 25 (12) ◽  
pp. 2017-2020 ◽  
Author(s):  
C. W. Carlson ◽  
J. P. McFadden ◽  
R. E. Ergun ◽  
M. Temerin ◽  
W. Peria ◽  
...  
Keyword(s):  
Electron Beams ◽  
Ion Heating ◽  
Current Region ◽  
Auroral Current

Dayside ionospheric electrodynamics in association with high-latitude dayside aurora (HiLDA)

2021 ◽  
Author(s):  
Lei Cai ◽  
Anita Kullen ◽  
Tomas Karlson ◽  
Andris Vaivads ◽  
Yongliang Zhang
Keyword(s):  
High Latitude ◽  
Large Scale ◽  
Potential Drop ◽  
Polar Cap ◽  
Ionospheric Electrodynamics ◽  
Defense Meteorological Satellite Program ◽  
Current Region ◽  
Fine Structures ◽  
Field Aligned Current ◽  
Set Up

&lt;p&gt;The Defense Meteorological Satellite Program (DMSP) Special Sensor Ultraviolet Spectrographic Imager (SSUSI) has observed the large-scale high-latitude dayside aurora (HiLDA) during its long lifetime of hours. HiLDA has dynamical changes in form, size, location, and development of fine structures. However, the associated electrodynamics is not fully understood. In general, HiLDA occurs in the dayside polar cap during IMF By+ (By-) prevailing conditions in the sunlit northern (southern) hemisphere.&amp;#160; The prevailing conditions drive strong upward field-aligned current in the polar cap. Within the upward field-aligned current region, the field-aligned potential drop can be set up and accelerate the electrons, forming the monoenergetic electron precipitation (up to 10s keV) and producing HiLDA.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;This study investigates the ionospheric flows, currents, and auroral precipitation in association with HiLDA, benified from the simultaneous measurements from the DMSP satellites, the AMPERE project, and ground-based magnetometers and SuperDARN coherent radars. We will show HiLDA interacts with duskside oval-aligned arcs or transpolar arcs. The interactions are associated with the cusp and the dayside reconnection at the duskside flank/high latitudes. The reconnection produces strong dusk-dawn convection with flow shears in the polar cap, which generates the upward Region 0 current. We find that HiLDA is formed in the high-latitude part of the upward Region 0 current. We apply the Knight relation and identify the lobe electrons (&lt; 0.3 cm&lt;sup&gt;-3&lt;/sup&gt;) as the source of HiLDA. The fine structures revealed in the emission intensity of HiLDA may suggest the uneven distribution of the electron density in the high-latitude lobe.&lt;/p&gt;

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

TAPERED WIGGLER FREE ELECTRON LASERS DRIVEN BY NON-MONOENERGETIC ELECTRON BEAMS

1983 ◽  
Vol 44 (C1) ◽  
pp. C1-371-C1-371 ◽  
Author(s):  
J. C. Goldstein ◽  
W. B. Colson ◽  
R. W. Warren
Keyword(s):  
Free Electron ◽  
Electron Beams ◽  
Free Electron Lasers ◽  
Monoenergetic Electron
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