scholarly journals Auroral particle acceleration by strong double layers: The upward current region

2004 ◽  
Vol 109 (A12) ◽  
Author(s):  
R. E. Ergun
Keyword(s):  
Particle Acceleration ◽  
Double Layers ◽  
Current Region ◽  
Upward Current

Conditions for establishing quasistable double layers in the Earth’s auroral upward current region

2010 ◽  
Vol 17 (12) ◽  
pp. 122901 ◽  
Author(s):  
D. S. Main ◽  
D. L. Newman ◽  
R. E. Ergun
Keyword(s):  
Double Layers ◽  
Current Region ◽  
Upward Current

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

Double layers and density cavitons in downward current region of aurora

2011 ◽  
Vol 23 (10) ◽  
pp. 2645-2649
Author(s):  
廖晶晶 Liao Jingjing ◽  
陈亮 Chen Liang ◽  
毛伊敏 Mao Yimin
Keyword(s):  
Double Layers ◽  
Current Region

Parallel electric fields in the upward current region of the aurora: Numerical solutions

2002 ◽  
Vol 9 (9) ◽  
pp. 3695-3704 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
D. Main ◽  
Y.-J. Su ◽  
D. L. Newman ◽  
...  
Keyword(s):  
Electric Fields ◽  
Numerical Solutions ◽  
Current Region ◽  
Upward Current

Ion acoustic solitons in Earth’s upward current region

2012 ◽  
Vol 19 (7) ◽  
pp. 072905 ◽  
Author(s):  
D. S. Main ◽  
D. L. Newman ◽  
C. Scholz ◽  
R. E. Ergun
Keyword(s):  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Current Region ◽  
Upward Current

Particle acceleration by double layers during kappa distributions

2007 ◽  
Vol 47 (4) ◽  
pp. 423-428 ◽  
Author(s):  
N. O. Ermakova ◽  
E. E. Antonova
Keyword(s):  
Particle Acceleration ◽  
Double Layers

scholarly journals Particle Acceleration Processes in the Solar Corona

1990 ◽  
Vol 43 (6) ◽  
pp. 703 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Particle Acceleration ◽  
Magnetic Reconnection ◽  
Electric Fields ◽  
Solar Flares ◽  
Double Layers ◽  
Historical Outline ◽  
Diffusive Acceleration ◽  
Phase Acceleration ◽  
Resonant Acceleration ◽  
Shock Fronts

Theoretical ideas on particle acceleration associated with solar flares are reviewed. A historical outline is used to introduce the various acceleration mechanisms. These are stochastic acceleration in its various forms, diffusive acceleration at shock fronts, shock drift acceleration, resonant acceleration, acceleration during magnetic reconnection and acceleration by parallel electric fields in double layers or electrostatic shocks. Particular emphasis is placed on so-called first phase acceleration of electrons in solar flares, which is conventionally attributed to bulk energisation of electrons (Ramaty et al. 1980). There is no widely accepted theory for bulk energisation, which may be regarded as an enhanced form of heating. Ideas on bulk energisation are discussed critically. It is argued that the dissipation cannot be due to classical resistivity and involves anomalous resistivity or hyperresistivity, e.g., in multiple double layers. The dissipation must occur in very many localised regions. Bulk energisation due to magnetic reconnection is discussed briefly. A model for bulk energisation due to the continual formation and decay of weak double layers is outlined

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