Turbulent anomalous transport and anisotropic electron heating in a return current system

2011 ◽  
Vol 18 (2) ◽  
pp. 022308 ◽  
Author(s):  
Kuang Wu Lee ◽  
Jörg Büchner
Keyword(s):  
Current System ◽  
Anomalous Transport ◽  
Return Current ◽  
Electron Heating

scholarly journals Collisionless Effects on Beam-Return Current Systems in Solar Flares

1985 ◽  
Vol 107 ◽  
pp. 521-525
Author(s):  
Loukas Vlahos ◽  
H. L. Rowland
Keyword(s):  
Solar Flares ◽  
Current System ◽  
Large Fraction ◽  
Coupled System ◽  
Impulsive Phase ◽  
Plasma Waves ◽  
Rate Equations ◽  
Return Current ◽  
Strong Turbulence ◽  
Current Systems

A large fraction of the electrons which are accelerated during the impulsive phase of solar flares stream towards the chromosphere and are unstable to the growth of plasma waves. The linear and nonlinear evolution of plasma waves as a function of time is analyzed with the use of a set of rate equations that follow in time the non-linearly coupled system of plasma waves-ion fluctuations. The nonthermal tail formed during the stabilization of the precipitated electrons can stabilize the Anomalous Doppler Resonance instability and prevent the isotropization of the energetic electrons. The precipitating electrons modify the way the return current is carried by the background plasma. In particular, the return current is not carried by the bulk of the electrons but by a small number of high velocity electrons. For beam/plasma densities ≳ 10−3, this can reduce the effects of collisions and heating by the return current. For higher density beams where the return current could be unstable to current driven instabilities, the effects of strong turbulence anomalous resistivity is shown to prevent the appearance of such instabilities. Our main conclusion is that the beam-return current system is interconnected and how the return current is carried is determined by the beam generated strong turbulence.

Evolution of a relativistic electron beam–plasma return current system

2009 ◽  
Vol 16 (3) ◽  
pp. 032107 ◽  
Author(s):  
X. Kong ◽  
J. Park ◽  
C. Ren ◽  
Z. M. Sheng ◽  
J. W. Tonge
Keyword(s):  
Electron Beam ◽  
Relativistic Electron ◽  
Relativistic Electron Beam ◽  
Current System ◽  
Return Current ◽  
Beam Plasma ◽  
Electron Beam Plasma

scholarly journals Three decades of research on the greater Agulhas Current

2006 ◽  
Vol 3 (4) ◽  
pp. 939-995 ◽  
Author(s):  
J. R. E. Lutjeharms
Keyword(s):  
Continental Shelf ◽  
Thermohaline Circulation ◽  
Current Knowledge ◽  
Current System ◽  
Knowledge Gaps ◽  
Return Current ◽  
Agulhas Current ◽  
Controversial Subject ◽  
The Past ◽  
New Information

Abstract. The greater Agulhas Current has been shown to be a key link in the global thermohaline circulation and an increased understanding of this current system is therefore of more than just local interest. Knowledge on the Agulhas Current system has in fact increased enormously over the past 30 years. This review covers some aspects of what has been learnt on the northern and the southern parts of the Agulhas Current proper and their influence on the waters and circulation of the adjoining continental shelf. It also discusses the Natal Pulse and new information that has been gained on how it is triggered and what influence it has. It deals with the Agulhas retroflection, the shedding of Agulhas rings and the movement and characteristics of these rings. The Agulhas Return Current forms the final outflow of the system and current knowledge on that current is appraised. The sources of the Agulhas Current have been a controversial subject for many years and this dispute continues. This is described and discussed, based on what information has been gained from research over the past three decades. Building on what is currently known, some suggestions are given on the most important remaining knowledge gaps and how these could most efficaciously be filled.

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