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

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)

scholarly journals Downward auroral currents from the reconnection Hall-region

2011 ◽  
Vol 29 (4) ◽  
pp. 679-685
Author(s):  
R. A. Treumann ◽  
R. Nakamura ◽  
W. Baumjohann
Keyword(s):  
Electromotive Force ◽  
Electron Flow ◽  
Electrons And Ions ◽  
Low Latitudes ◽  
Outflow Region ◽  
Current Region ◽  
Collisionless Reconnection ◽  
Downward Currents ◽  
Auroral Current ◽  
Fast Reconnection

Abstract. We present a simple (stationary) mechanism capable of generating the auroral downward field-aligned electric field that is needed for accelerating the ionospheric electron component up into the magnetosphere and confining the ionospheric ions at low latitudes (as is required by observation of an ionospheric cavity in the downward auroral current region). The lifted ionospheric electrons carry the downward auroral current. Our model is based on the assumption of collisionless reconnection in the tail current sheet. It makes use of the dynamical difference between electrons and ions in the ion inertial region surrounding the reconnection X-line which causes Hall currents to flow. We show that the spatial confinement of the Hall magnetic field and flux to the ion inertial region centred on the X-point generates a spatially variable electromotive force which is positive near the outer inflow boundaries of the ion inertial region and negative in the central inflow region. Looked at from the ionosphere it functions like a localised meso-scale electric potential. The positive electromotive force gives rise to upward electron flow from the ionosphere during substorms (causing "black aurorae"). A similar positive potential is identified on the earthward side of the fast reconnection outflow region which has the same effect, explaining the observation that auroral upward currents are flanked from both sides by narrow downward currents.

scholarly journals Low-Altitude Ion Heating, Downflowing Ions, and BBELF Waves in the Return Current Region

2018 ◽  
Vol 123 (4) ◽  
pp. 3087-3110 ◽  
Author(s):  
Yangyang Shen ◽  
David J. Knudsen ◽  
Johnathan K. Burchill ◽  
Andrew D. Howarth ◽  
Andrew W. Yau ◽  
...  
Keyword(s):  
Ion Heating ◽  
Return Current ◽  
Current Region ◽  
Low Altitude

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

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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