Electron temperature anisotropy constraints in the solar wind

2008 ◽  
Vol 113 (A3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Štěpán Štverák ◽  
Pavel Trávníček ◽  
Milan Maksimovic ◽  
Eckart Marsch ◽  
Andrew N. Fazakerley ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electron Temperature ◽  
Temperature Anisotropy

scholarly journals Electron Temperature Anisotropy and Electron Beam Constraints from Electron Kinetic Instabilities in the Solar Wind

2020 ◽  
Vol 902 (1) ◽  
pp. 59
Author(s):  
Heyu Sun ◽  
Jinsong Zhao ◽  
Wen Liu ◽  
Huasheng Xie ◽  
Dejin Wu
Keyword(s):  
Solar Wind ◽  
Electron Beam ◽  
Electron Temperature ◽  
Temperature Anisotropy ◽  
Kinetic Instabilities

scholarly journals Particle-in-cell Simulations of the Parallel Proton Firehose Instability Influenced by the Electron Temperature Anisotropy in Solar Wind Conditions

2020 ◽  
Vol 893 (2) ◽  
pp. 130 ◽  
Author(s):  
A. Micera ◽  
E. Boella ◽  
A. N. Zhukov ◽  
S. M. Shaaban ◽  
R. A. López ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electron Temperature ◽  
Temperature Anisotropy ◽  
Particle In Cell

scholarly journals Effects of Electron Temperature Anisotropy on Proton-beam Instability in the Solar Wind

2020 ◽  
Vol 899 (1) ◽  
pp. 61
Author(s):  
L. Xiang ◽  
K. H. Lee ◽  
D. J. Wu ◽  
L. C. Lee
Keyword(s):  
Solar Wind ◽  
Electron Temperature ◽  
Proton Beam ◽  
Beam Instability ◽  
Temperature Anisotropy

Electron Kinetic Instability Driven by Electron Temperature Anisotropy and Electron Beam in the Solar Wind

2020 ◽  
Author(s):  
Jinsong Zhao ◽  
Heyu Sun ◽  
Wen Liu ◽  
Huasheng Xie ◽  
Dejin Wu
Keyword(s):  
Solar Wind ◽  
Electron Beam ◽  
Electron Temperature ◽  
Electron Dynamics ◽  
Temperature Anisotropy ◽  
Acoustic Instability ◽  
Beam Velocity ◽  
Kinetic Instability ◽  
Electron Acoustic ◽  
Beam Component

<p>Electron temperature anisotropy instabilities are believed to constrain the distributions of the electron parallel and perpendicular temperatures in the solar wind. When the electron perpendicular temperature is larger than the parallel temperature, the whistler instability is normally stronger than the electron mirror instability. While the electron parallel temperature is larger than the perpendicular temperature, the electron oblique firehose instability dominates the parallel firehose instability. Therefore, previous studies proposed the whistler and electron oblique firehose instabilities constraint on the electron dynamics in the solar wind. Based on the fact that there always exists the differential drift velocity among different electron populations, we consider the electron kinetic instability in the plasmas containing the electron anisotropic component and the electron beam component. Consequently, we give a comprehensive electron kinetic instability analysis in the solar wind. Furthermore, we propose that the electron acoustic/magneto-acoustic instability can arise in the low electron beta regime, and the whistler electron beam instability can be triggered in a wide beta regime. These two instabilities can provide a constraint on the electron beam velocity. Moreover, we find a new instability in the regime of the electron beta ~ 1, and this instability produces obliquely-propagating fast-magnetosonic/whistler waves. These results would be helpful for distinguishing the electron instability and for analyzing the constraint mechanism on the electron temperature distribution in the solar wind.</p>

scholarly journals Tests for coronal electron temperature signatures in suprathermal electron populations at 1 AU

2017 ◽  
Vol 35 (6) ◽  
pp. 1275-1291 ◽  
Author(s):  
Allan R. Macneil ◽  
Christopher J. Owen ◽  
Robert T. Wicks
Keyword(s):  
Solar Wind ◽  
Electron Temperature ◽  
Energy Content ◽  
The Sun ◽  
Particle Interactions ◽  
Core Electron ◽  
Suprathermal Electron ◽  
Electron Distributions ◽  
The Relationship ◽  
Coronal Electron

Abstract. The development of knowledge of how the coronal origin of the solar wind affects its in situ properties is one of the keys to understanding the relationship between the Sun and the heliosphere. In this paper, we analyse ACE/SWICS and WIND/3DP data spanning  > 12 years, and test properties of solar wind suprathermal electron distributions for the presence of signatures of the coronal temperature at their origin which may remain at 1 AU. In particular we re-examine a previous suggestion that these properties correlate with the oxygen charge state ratio O7+ ∕ O6+, an established proxy for coronal electron temperature. We find only a very weak but variable correlation between measures of suprathermal electron energy content and O7+ ∕ O6+. The weak nature of the correlation leads us to conclude, in contrast to earlier results, that an initial relationship with core electron temperature has the possibility to exist in the corona, but that in most cases no strong signatures remain in the suprathermal electron distributions at 1 AU. It cannot yet be confirmed whether this is due to the effects of coronal conditions on the establishment of this relationship or due to the altering of the electron distributions by processing during transport in the solar wind en route to 1 AU. Contrasting results for the halo and strahl population favours the latter interpretation. Confirmation of this will be possible using Solar Orbiter data (cruise and nominal mission phase) to test whether the weakness of the relationship persists over a range of heliocentric distances. If the correlation is found to strengthen when closer to the Sun, then this would indicate an initial relationship which is being degraded, perhaps by wave–particle interactions, en route to the observer.

Electromagnetic electron temperature anisotropy instabilities

1985 ◽  
Vol 90 (A8) ◽  
pp. 7607-7610 ◽  
Author(s):  
S. Peter Gary ◽  
Christian D. Madland
Keyword(s):  
Electron Temperature ◽  
Temperature Anisotropy

Analysis of Alfvénic flows with Solar Orbiter: particle and magnetic observations down to kinetic scales.

2021 ◽  
Author(s):  
Philippe Louarn ◽  
Andrei fedorov ◽  
alexis Rouillard ◽  
Benoit Lavraud ◽  
Vincent Génot ◽  
...  
Keyword(s):  
Solar Wind ◽  
Fine Structure ◽  
Time Resolution ◽  
Time Scale ◽  
Residual Energy ◽  
Distribution Functions ◽  
Strongly Correlated ◽  
Temperature Anisotropy ◽  
Velocity Fluctuations ◽  
Turbulence Parameters

<p>The magnetic and velocity fluctuations of the solar wind may be strongly correlated. This characterizes the  ‘Alfvenic’ flows. Using the observations of the Proton Alfa sensor (PAS/SWA) and the magnetometer (MAG) onboard Solar Orbiter, we analyze a period of 100 hours of such alfvenic flows, at different scales. Several parameters of the turbulence are computed (V-B correlation, various spectral indexes, cross-helicity, residual energy). We explore how these parameters may vary with time and characterize different turbulent states of the flow. More specifically, using the unprecedented time resolution of PAS during burst mode, especially its capability to measure 3D distribution functions at time scale below the proton gyroperiod, we study the connection of the turbulence to the dissipation domain and analyze the fine structure of the distribution functions and their evolutions at sub-second scales. The goal is to investigate whether some characteristics of the distributions, as their more or less pronounced temperature anisotropy, may be related to the turbulence parameters and the degree of V-B correlation.</p>

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