Effect of the electric field on the agyrotropic electron distributions

2021 ◽  
Author(s):  
C. ‐H. Gao ◽  
B. ‐B. Tang ◽  
W. Y. Li ◽  
C. Wang ◽  
Yu. V. Khotyaintsev ◽  
...  
Keyword(s):  
Electric Field ◽  
Electron Distributions

scholarly journals Parker Solar Probe Evidence for the Absence of Whistlers Close to the Sun to Scatter Strahl and to Regulate Heat Flux

2022 ◽  
Vol 924 (2) ◽  
pp. L33
Author(s):  
C. Cattell ◽  
A. Breneman ◽  
J. Dombeck ◽  
E. Hanson ◽  
M. Johnson ◽  
...  
Keyword(s):  
Heat Flux ◽  
Electric Field ◽  
Acoustic Waves ◽  
Electron Distribution Function ◽  
The Sun ◽  
Temperature Anisotropy ◽  
Ion Acoustic Waves ◽  
Plasma Properties ◽  
Electron Distributions ◽  
Whistler Mode Waves

Abstract Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from ∼16 R s to ∼130 R s, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside ∼28 R s (∼0.13 au). Outside 28 R s, they occur within a narrow range of parallel electron beta from ∼1 to 10, and with a beta-heat flux occurrence consistent with the whistler heat flux fan instability. Because electron distributions inside ∼30 R s display signatures of the ambipolar electric field, the lack of whistlers suggests that the modification of the electron distribution function associated with the ambipolar electric field or changes in other plasma properties must result in lower instability limits for the other modes (including the observed solitary waves and ion acoustic waves) that are observed close to the Sun. The lack of narrowband whistler-mode waves close to the Sun and in regions of either low (<0.1) or high (>10) beta is also significant for the understanding and modeling of the evolution of flare-accelerated electrons and the regulation of heat flux in astrophysical settings including other stellar winds, the interstellar medium, accretion disks, and the intragalaxy cluster medium.

scholarly journals Attenuation of Plasmaspheric Hiss Associated with the Enhanced Magnetospheric Electric Field

2021 ◽  
Author(s):  
Haimeng Li ◽  
Wen Li ◽  
Qianli Ma ◽  
Yukitoshi Nishimura ◽  
Zhigang Yuan ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Energetic Electron ◽  
Wave Intensity ◽  
Wave Amplification ◽  
Model Driven ◽  
Van Allen Probes ◽  
Electron Distributions ◽  
New Finding ◽  
Substorm Activity

Abstract. We report an attenuation of hiss wave intensity in the duskside of outer plasmasphere in response to enhanced convection and substorm based on Van Allen Probes observations. Using test particle codes, we simulate the dynamics of energetic electron fluxes based on a realistic magnetospheric electric field model driven by solar wind and subauroral polarization stream. We suggest that the enhanced magnetospheric electric field causes the outward and sunward motion of energetic electrons, corresponding to the decrease of energetic electron fluxes on the duskside, leading to the subsequent attenuation of hiss wave intensity. The results indicate that the enhanced electric field can significantly change the energetic electron distributions, which provide free energy for hiss wave amplification. This new finding is critical for understanding the generation of plasmaspheric hiss and its response to solar wind and substorm activity.

scholarly journals An event study on broadband electric field noises and electron distributions in the lunar wake boundary

2022 ◽  
Vol 74 (1) ◽  
Author(s):  
Masaki N. Nishino ◽  
Yoshiya Kasahara ◽  
Yuki Harada ◽  
Yoshifumi Saito ◽  
Hideo Tsunakawa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Electric Field ◽  
Interplanetary Magnetic Field ◽  
Electric Fields ◽  
Lunar Surface ◽  
Electron Beams ◽  
The Moon ◽  
Link Type ◽  
Electron Distributions

AbstractWave–particle interactions are fundamental processes in space plasma, and some plasma waves, including electrostatic solitary waves (ESWs), are recognised as broadband noises (BBNs) in the electric field spectral data. Spacecraft observations in recent decades have detected BBNs around the Moon, but the generation mechanism of the BBNs is not fully understood. Here, we study a wake boundary traversal with BBNs observed by Kaguya, which includes an ESW event previously reported by Hashimoto et al. Geophys Res Lett 37:L19204 10.1029/2010GL044529 (2010). Focusing on the relation between BBNs and electron pitch-angle distribution functions, we show that upward electron beams from the nightside lunar surface are effective for the generation of BBNs, in contrast to the original interpretation by Hashimoto et al. Geophys Res Lett 37:L19204 10.1029/2010GL044529 (2010) that high-energy electrons accelerated by strong ambipolar electric fields excite ESWs in the region far from the Moon. When the BBNs were observed by the Kaguya spacecraft in the wake boundary, the spacecraft’s location was magnetically connected to the nightside lunar surface, and bi-streaming electron distributions of downward-going solar wind strahl component and upward-going field-aligned beams (at $$\sim$$ ∼ 124 eV) were detected. The interplanetary magnetic field was dominated by a positive $$B_Z$$ B Z (i.e. the northward component), and strahl electrons travelled in the antiparallel direction to the interplanetary magnetic field (i.e. southward), which enabled the strahl electrons to precipitate onto the nightside lunar surface directly. The incident solar wind electrons cause negative charging of the nightside lunar surface, which generates downward electric fields that accelerate electrons from the nightside surface toward higher altitudes along the magnetic field. The bidirectional electron distribution is not a sufficient condition for the BBN generation, and the distribution of upward electron beams seems to be correlated with the BBNs. Ambipolar electric fields in the wake boundary should also contribute to the electron acceleration toward higher altitudes and further intrusion of the solar wind ions into the deeper wake. We suggest that solar wind ion intrusion into the wake boundary is also an important factor that controls the BBN generation by facilitating the influx of solar wind electrons there. Graphical Abstract

scholarly journals Attenuation of plasmaspheric hiss associated with the enhanced magnetospheric electric field

2021 ◽  
Vol 39 (3) ◽  
pp. 461-470
Author(s):  
Haimeng Li ◽  
Wen Li ◽  
Qianli Ma ◽  
Yukitoshi Nishimura ◽  
Zhigang Yuan ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Field Model ◽  
Energetic Electron ◽  
Wave Intensity ◽  
Wave Amplification ◽  
Model Driven ◽  
Electron Distributions ◽  
New Finding ◽  
Substorm Activity

Abstract. We report an attenuation of hiss wave intensity in the duskside of the outer plasmasphere in response to enhanced convection and a substorm based on Van Allen Probe observations. Using test particle codes, we simulate the dynamics of energetic electron fluxes based on a realistic magnetospheric electric field model driven by solar wind and subauroral polarization stream. We suggest that the enhanced magnetospheric electric field causes the outward and sunward motion of energetic electrons, corresponding to the decrease of energetic electron fluxes on the duskside, leading to the subsequent attenuation of hiss wave intensity. The results indicate that the enhanced electric field can significantly change the energetic electron distributions, which provide free energy for hiss wave amplification. This new finding is critical for understanding the generation of plasmaspheric hiss and its response to solar wind and substorm activity.

Electron Bernstein waves Driven by the Parallel Electron Crescent in the Reconnection Exhaust Region

2020 ◽  
Author(s):  
Kyunghwan Dokgo ◽  
Kyoung-Joo Hwang ◽  
James L. Burch ◽  
Peter H. Yoon ◽  
Daniel B. Graham ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Electric Field ◽  
High Frequency ◽  
Diffusion Region ◽  
Linear Dispersion ◽  
Frequency Wave ◽  
Bernstein Waves ◽  
Electron Distributions ◽  
High Frequency Waves ◽  
Numerical Solver

&lt;p&gt;The recently launched NASA&amp;#8217;s Magnetosphere Multiscale (MMS) mission enables investigations of multi-scale phenomena in the reconnection process. Especially, the MMS spacecraft revealed that high-frequency waves of electron time scales exist near the electron diffusion region (EDR) due to complex electron distributions. As such waves are generated near the EDR, they could significantly affect the environment of the EDR via wave-particle interactions.&lt;/p&gt;&lt;p&gt;&amp;#160;We investigated the September 19, 2015 event when the MMS spacecraft crossed the reconnection exhaust region. The MMS spacecraft observed a parallel electron crescent, which is known to be generated by the cyclotron turning due to the normal magnetic field in the reconnection exhaust region. At the same time, highly discrete waves were observed in the power spectrum of the electric field. The wave frequency ranged between 6 &amp;#160;~ 14 Fce (Fce: electron cyclotron frequency), and the power of perpendicular components was larger than the parallel component. Therefore, they featured electron Bernstein waves. By modeling the parallel electron crescent as a sum of 18 ring-shaped electron distributions, we calculate the linear dispersion relation using a numerical solver. The linear growth rates agreed with the power spectrum of the electric field, which means that the parallel electron crescent locally drove the electron Bernstein waves. Together with previous studies of high-frequency waves, our work could provide a diagram of high-frequency wave distributions in the reconnection geometry.&lt;/p&gt;

Infrared diode laser and microwave spectroscopy of molecular ions

1988 ◽  
Vol 324 (1578) ◽  
pp. 131-139 ◽  
Keyword(s):  
Electric Field ◽  
Diode Laser ◽  
Simple Procedure ◽  
Molecular Ions ◽  
Microwave Spectroscopy ◽  
Experimental Results ◽  
Fermi Interaction ◽  
Isoelectronic Series ◽  
Electron Distributions ◽  
Feynman Theorem

Some of the recent results on FHF - , HBF + , H 2 C1 + , H3S+, HCO + , and DCO + are reviewed. The last two molecules are studied to detect the effect of the discharge electric field on 1-type doublets in the v 2 = 1 and = v 2 -2 states. The Fermi interaction between v 1 and 4 v 2 in DCO + is also discussed. These experimental results are followed by introduction of a simple procedure, based upon the Hellmann-Feynman theorem, that allows us to estimate the electron distributions in ions in comparison with those in related neutrals. Three isoelectronic series (1) NH - , OH and FH + , (2) HBF + , HBO, HCO + , HCN, HNN + , HNC and HOC + , and (3) NH 2 , OH 2 and FH 2 are discussed by this method.

scholarly journals Electron acceleration by a localized electric field

1986 ◽  
Vol 4 (3-4) ◽  
pp. 439-452 ◽  
Author(s):  
D. Galmiche ◽  
J. P. Nicolle ◽  
D. Pesme
Keyword(s):  
Particle Acceleration ◽  
Electric Field ◽  
Plasma Wave ◽  
Electron Acceleration ◽  
Landau Damping ◽  
One Dimensional ◽  
Convective Regime ◽  
Electric Structure ◽  
Electron Distributions

The acceleration of test electrons by a resonant, one—dimensional electric structure is studied in the convective regime with the Zakharov equations. Depending on the nonlinearity level the particle acceleration is due to diffusion or trapping by the plasma wave. Electron distributions are obtained and compared with 1-D particle code results. Influence of Landau damping formulation is discussed.

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