scholarly journals BeiDa Imaging Electron Spectrometer observation of multi-period electron flux modulation caused by localized ultra-low-frequency waves

2020 ◽  
Vol 38 (4) ◽  
pp. 801-813
Author(s):  
Xingran Chen ◽  
Qiugang Zong ◽  
Hong Zou ◽  
Xuzhi Zhou ◽  
Li Li ◽  
...  
Keyword(s):  
Time Delay ◽  
Electron Flux ◽  
Particle Interaction ◽  
Energetic Electron ◽  
Low Frequency ◽  
Particle Energy ◽  
Energy Change ◽  
Electron Spectrometer ◽  
Resonance Theory ◽  
Energy Channels

Abstract. We present multi-period modulation of energetic electron flux observed by the BeiDa Imaging Electron Spectrometer (BD-IES) on board a Chinese navigation satellite on 13 October 2015. Electron flux oscillations were observed at a dominant period of ∼190 s in consecutive energy channels from ∼50 to ∼200 keV. Interestingly, flux modulations at a secondary period of ∼400 s were also unambiguously observed. The oscillating signals at different energy channels were observed in sequence, with a time delay of up to ∼900 s. This time delay far exceeds the oscillating periods, by which we speculate that the modulations were caused by localized ultra-low-frequency (ULF) waves. To verify the wave–particle interaction scenario, we revisit the classic drift-resonance theory. We adopt the calculation method therein to derive the electron energy change in a multi-period ULF wave field. Then, based on the modeled energy change, we construct the flux variations to be observed by a virtual spacecraft. The predicted particle signatures well agree with the BD-IES observations. We demonstrate that the particle energy change might be underestimated in the conventional theories, as the Betatron acceleration induced by the curl of the wave electric field was often omitted. In addition, we show that azimuthally localized waves would notably extend the energy width of the resonance peak, whereas the drift-resonance interaction is only efficient for particles at the resonant energy in the original theory.

scholarly journals BD-IES Observation of Multi-Period Electron Flux Modulation Caused by Localized Ultra-Low Frequency Waves

2019 ◽  
Author(s):  
Xingran Chen ◽  
Qiugang Zong ◽  
Hong Zou ◽  
Xuzhi Zhou ◽  
Li Li ◽  
...  
Keyword(s):  
Time Delay ◽  
Electron Flux ◽  
Particle Interaction ◽  
Energetic Electron ◽  
Low Frequency ◽  
Particle Energy ◽  
Energy Change ◽  
Resonance Theory ◽  
Electron Field ◽  
Energy Channels

Abstract. We present multi-period modulation of energetic electron flux observed by the BeiDa Imaging Electron Spectrometer (BD-IES) onboard a Chinese navigation satellite on October 13, 2015. Electron flux oscillations were observed at a dominant period of ~ 190 s in consecutive energy channels from ~ 50 keV to ~ 200 keV. Interestingly, flux modulations at a secondary period of ~ 400 s were also unambiguously observed. The oscillating signals at different energy channels were observed in sequence, with a time delay of up to ~ 900 s. This time delay far exceeds the oscillating periods, by which we speculate that the modulations were caused by localized ultra-low frequency (ULF) waves. To verify the wave-particle interaction scenario, we revisit the classic drift-resonance theory. We adopt the calculation scheme therein to derive the electron energy change in a multi-period ULF wave field. Then, based on the modeled energy change, we construct the flux variations to be observed by a virtual spacecraft. The predicted particle signatures well agree with the BD-IES observations. We demonstrate that the particle energy change might be underestimated in the conventional theories, as the Betatron acceleration induced by the curl of the wave electron field was often omitted. In addition, we show that azimuthally localized waves would notably extend the energy width of the resonance peak, whereas the drift-resonance interaction is only efficient for particles at the resonant energy in the original theory.

scholarly journals Strong localized variations of the low-altitude energetic electron fluxes in the evening sector near the plasmapause

1998 ◽  
Vol 16 (1) ◽  
pp. 25-33 ◽  
Author(s):  
E. E. Titova ◽  
T. A. Yahnina ◽  
A. G. Yahnin ◽  
B. B. Gvozdevsky ◽  
A. A. Lyubchich ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Electron Flux ◽  
Particle Interaction ◽  
Energetic Electron ◽  
Recovery Phase ◽  
Electron Precipitation ◽  
Statistical Characteristics ◽  
Evening Sector ◽  
Proton Precipitation ◽  
Low Altitude

Abstract. Specific type of energetic electron precipitation accompanied by a sharp increase in trapped energetic electron flux are found in the data obtained from low-altitude NOAA satellites. These strongly localized variations of the trapped and precipitated energetic electron flux have been observed in the evening sector near the plasmapause during recovery phase of magnetic storms. Statistical characteristics of these structures as well as the results of comparison with proton precipitation are described. We demonstrate the spatial coincidence of localized electron precipitation with cold plasma gradient and whistler wave intensification measured on board the DE-1 and Aureol-3 satellites. A simultaneous localized sharp increase in both trapped and precipitating electron flux could be a result of significant pitch-angle isotropization of drifting electrons due to their interaction via cyclotron instability with the region of sharp increase in background plasma density.Key words. Ionosphere (particle precipitation; wave-particle interaction) Magnetospheric Physics (plasmasphere)

scholarly journals Van Allen Probes observation of plasmaspheric hiss modulated by injected energetic electrons

2018 ◽  
Vol 36 (3) ◽  
pp. 781-791 ◽  
Author(s):  
Run Shi ◽  
Wen Li ◽  
Qianli Ma ◽  
Seth G. Claudepierre ◽  
Craig A. Kletzing ◽  
...  
Keyword(s):  
Plasma Density ◽  
Direct Evidence ◽  
Electron Flux ◽  
Energetic Electron ◽  
Low Frequency ◽  
Wave Intensity ◽  
Electron Population ◽  
Ulf Wave ◽  
Van Allen Probes ◽  
First Time

Abstract. Plasmaspheric hiss was observed by Van Allen Probe B in association with energetic electron injections in the outer plasmasphere. The energy of injected electrons coincides with the minimum resonant energy calculated for the observed hiss wave frequency. Interestingly, the variations in hiss wave intensity, electron flux and ultra low frequency (ULF) wave intensity exhibit remarkable correlations, while plasma density is not correlated with any of these parameters. Our study provides direct evidence for the first time that the injected anisotropic electron population, which is modulated by ULF waves, modulates the hiss intensity in the outer plasmasphere. This also implies that the plasmaspheric hiss observed by Van Allen Probe B in the outer plasmasphere (L > ∼ 5.5) is locally amplified. Meanwhile, Van Allen Probe A observed hiss emission at lower L shells (< 5), which was not associated with electron injections but primarily modulated by the plasma density. The features observed by Van Allen Probe A suggest that the observed hiss deep inside the plasmasphere may have propagated from higher L shells.

scholarly journals On the wave-particle interaction and removal of energetic particles

2021 ◽  
Vol 48 (4) ◽  
Author(s):  
Umesh P. Singh ◽  
Keyword(s):  
Particle Interaction ◽  
Energetic Electron ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Low Earth Orbit ◽  
Frequency Range ◽  
Geomagnetic Field Line ◽  
Energetic Electrons ◽  
Low Latitudes ◽  
Whistler Mode Waves

There is always a risk of destruction of man-made satellites by the energetic electrons trapped in Van Allen radiation belts in space. These energetic electrons also pose a biological danger to astronauts. The cyclotron resonance interaction is studied between the whistler-mode waves in the frequency range of ELF (Extremely Low Frequency 300 – 3000 HZ) and VLF (Very Low Frequency 3 – 30 kHz) propagating along geomagnetic field line and counter streaming energetic electron. During this process the pitch angle of energetic electrons reduces. This results in the dumping of these electrons into the lower ionosphere. This makes electrons unable to strike the satellites orbiting in low Earth orbit, Geosynchronous, Sun-synchronous or polar orbit. It is shown that the lifetime values of energetic electrons vary from 2.03 to 227.68 hours at low latitudes. It is shown that these waves can remove these energetic electrons from their path and ensure the safety of satellites.

Observations and simulations of electron flux oscillations in response to broadband ULF waves

2020 ◽  
Author(s):  
Xinlin Li ◽  
Theodoros Sarris ◽  
Michael Temerin ◽  
Hong Zhao ◽  
Leng Ying Khoo ◽  
...  
Keyword(s):  
Electron Flux ◽  
Low Frequency ◽  
Transport Processes ◽  
Ulf Waves ◽  
Magnetic Fluctuations ◽  
Radial Transport ◽  
Energy Channel ◽  
Van Allen Probes ◽  
Initial Results ◽  
Energy Channels

&lt;p&gt;It has recently been demonstrated through simulations and observations that flux oscillations of hundreds-keV electrons are produced in the magnetosphere in association with broadband Ultra Low Frequency (ULF) waves (Sarris et al., JGR, 2017). These oscillations are observed in the form of drift-periodic flux fluctuations, but are not associated with drift echoes following storm- or substorm-related energetic particle injections. They are observed in particular during quiet times, and it has been shown that they could indicate ongoing radial transport processes caused by ULF waves. It has also been shown that the width of electron energy channels is a critical parameter affecting the observed amplitude of flux oscillations, with narrower energy channel widths enabling the observation of higher-amplitude flux oscillations; this potentially explains why such features were not observed regularly before the Van Allen Probes era, as previous spacecraft generally had lower energy resolution. We extend these initial results by investigating the association between the observed flux oscillations with the amplitude of electric and magnetic fluctuations in the ULF range and with Phase Space Density gradients, both of which are expected to also affect radial transport rates.&lt;/p&gt;

scholarly journals Comparison of energetic electron flux and phase space density in the magnetosheath and in the magnetosphere

2012 ◽  
Vol 117 (A5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Bingxian Luo ◽  
Xinlin Li ◽  
Weichao Tu ◽  
Jiancun Gong ◽  
Siqing Liu
Keyword(s):  
Phase Space ◽  
Electron Flux ◽  
Energetic Electron ◽  
Phase Space Density ◽  
Space Density

scholarly journals Multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an intense solar wind dynamic pressure pulse

2016 ◽  
Vol 34 (5) ◽  
pp. 493-509 ◽  
Author(s):  
Zheng Xiang ◽  
Binbin Ni ◽  
Chen Zhou ◽  
Zhengyang Zou ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Pressure Pulse ◽  
Electron Flux ◽  
Dynamic Pressure ◽  
Energetic Electron ◽  
Solar Wind Dynamic Pressure ◽  
Angle Scattering ◽  
Radiation Belt Electrons ◽  
Atmospheric Loss

<p><strong>Abstract.</strong> Radiation belt electron flux dropouts are a kind of drastic variation in the Earth's magnetosphere, understanding of which is of both scientific and societal importance. Using electron flux data from a group of 14 satellites, we report multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an event of intense solar wind dynamic pressure pulse. When the pulse occurred, magnetopause and atmospheric loss could take effect concurrently contributing to the electron flux dropout. Losses through the magnetopause were observed to be efficient and significant at <i>L</i> ≳ 5, owing to the magnetopause intrusion into <i>L</i> ∼ 6 and outward radial diffusion associated with sharp negative gradient in electron phase space density. Losses to the atmosphere were directly identified from the precipitating electron flux observations, for which pitch angle scattering by plasma waves could be mainly responsible. While the convection and substorm injections strongly enhanced the energetic electron fluxes up to hundreds of keV, they could delay other than avoid the occurrence of electron flux dropout at these energies. It is demonstrated that the pulse-time radiation belt electron flux dropout depends strongly on the specific interplanetary and magnetospheric conditions and that losses through the magnetopause and to the atmosphere and enhancements of substorm injection play an essential role in combination, which should be incorporated as a whole into future simulations for comprehending the nature of radiation belt electron flux dropouts.</p>

scholarly journals Comparison between CNA and energetic electron precipitation: simultaneous observation by Poker Flat Imaging Riometer and NOAA satellite

2005 ◽  
Vol 23 (5) ◽  
pp. 1555-1563 ◽  
Author(s):  
Y.-M. Tanaka ◽  
M. Ishii ◽  
Y. Murayama ◽  
M. Kubota ◽  
H. Mori ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Electron Precipitation ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Loss Cone ◽  
Isotropic Pitch ◽  
Trapped Electron

Abstract. The cosmic noise absorption (CNA) is compared with the precipitating electron flux for 19 events observed in the morning sector, using the high-resolution data obtained during the conjugate observations with the imaging riometer at Poker Flat Research Range (PFRR; 65.11° N, 147.42° W), Alaska, and the low-altitude satellite, NOAA 12. We estimate the CNA, using the precipitating electron flux measured by NOAA 12, based on a theoretical model assuming an isotropic pitch angle distribution, and quantitatively compare them with the observed CNA. Focusing on the eight events with a range of variation larger than 0.4dB, three events show high correlation between the observed and estimated CNA (correlation coefficient (r0)>0.7) and five events show low correlation (r0<0.5). The estimated CNA is often smaller than the observed CNA (72% of all data for 19 events), which appears to be the main reason for the low-correlation events. We examine the assumption of isotropic pitch angle distribution by using the trapped electron flux measured at 80° zenith angle. It is shown that the CNA estimated from the trapped electron flux, assuming an isotropic pitch angle distribution, is highly correlated with the observed CNA and is often overestimated (87% of all data). The underestimate (overestimate) of CNA derived from the precipitating (trapped) electron flux can be interpreted in terms of the anisotropic pitch angle distribution similar to the loss cone distribution. These results indicate that the CNA observed with the riometer may be quantitatively explained with a model based on energetic electron precipitation, provided that the pitch angle distribution and the loss cone angle of the electrons are taken into account. Keywords. Energetic particles, precipitating – Energetic particles, trapped – Ionosphere-magnetosphere interactions

scholarly journals Inverse Compton Scattering in pulsar physics

1996 ◽  
Vol 160 ◽  
pp. 159-162
Author(s):  
G.J. Qiao
Keyword(s):  
Radio Emission ◽  
Compton Scattering ◽  
Low Frequency ◽  
Position Angle ◽  
High Energy ◽  
Particle Energy ◽  
Important Process ◽  
Frequency Wave ◽  
Inverse Compton Scattering ◽  
Inverse Compton

AbstractInverse Compton Scattering (ICS) is a very important process not only in inner gap physics, but also for radio emission. ICS of high energy particles with thermal photons is the dominant and a very efficient mechanism of the particle energy loss above the neutron star surface, and is an important process in causing gap breakdown. The pulsar distribution in theP−Pdiagram and the observed mode changing phenomenon of some pulsars can be expained by the sparking conditions due to ICS. ICS of the secondary particles with the low frequency wave from the inner gap sparking can be responsible for radio emission. In this ICS model, many observational features of pulsar radio emission can be explained, such as: one core and two conal emission components, their different emission altitudes and relative time delay effects; spectral behavior of pulse profiles; the behavior of the linear polarization and position angle.

Sign in / Sign up

Export Citation Format

Share Document