Roles of Magnetospheric Convection on Nonlinear Drift Resonance Between Electrons and ULF Waves

2020 ◽  
Vol 125 (6) ◽  
Author(s):  
Li Li ◽  
Yoshiharu Omura ◽  
Xu‐Zhi Zhou ◽  
Qiu‐Gang Zong ◽  
Sui‐Yan Fu ◽  
...  
Keyword(s):  
Ulf Waves ◽  
Magnetospheric Convection

Roles of magnetospheric convection on nonlinear drift resonance between electrons and ULF waves

2020 ◽  
Author(s):  
Xuzhi Zhou ◽  
Li Li ◽  
Yoshiharu Omura ◽  
Qiugang Zong ◽  
Suiyan Fu ◽  
...  
Keyword(s):  
Distribution Functions ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Ultralow Frequency ◽  
Magnetospheric Convection ◽  
Ulf Wave ◽  
Pendulum Equation ◽  
Drift Frequency ◽  
Strong Convection ◽  
Trapping Frequency

<p>In the Earth's inner magnetosphere, charged particles can be accelerated and transported by ultralow frequency (ULF) waves via drift resonance. We investigate the effects of magnetospheric convection on the nonlinear drift resonance process, which provides an inhomogeneity factor S to externally drive the pendulum equation that describes the particle motion in the ULF wave  field. The S factor, defined as the ratio of the driving amplitude to the square of the pendulum trapping frequency, is found to vary with magnetic local time and as a consequence, oscillates quasi-periodically at the particle drift frequency. To better understand the particle behavior governed by the driven pendulum equation, we carry out simulations to obtain the evolution of electron distribution functions in energy and L-shell phase space. We find that resonant electrons can remain trapped by the low-m ULF waves under strong convection electric  field, whereas for high-m ULF waves, the electrons trajectories can be significantly modified. More interestingly, the electron drift frequency is close to the nonlinear trapping frequency for intermediate-m ULF waves, which corresponds to chaotic motion of resonant electrons. These  findings shed new light on the nature of particle coherent and diffusive transport in the inner magnetosphere.</p>

scholarly journals Long-Lasting Poloidal ULF Waves Observed by Multiple Satellites and High-Latitude SuperDARN Radars

2018 ◽  
Vol 123 (10) ◽  
pp. 8422-8438 ◽  
Author(s):  
X. Shi ◽  
J. B. H. Baker ◽  
J. M. Ruohoniemi ◽  
M. D. Hartinger ◽  
K. R. Murphy ◽  
...  
Keyword(s):  
High Latitude ◽  
Ulf Waves

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

Multisatellite studies of ULF waves

1988 ◽  
Vol 8 (9-10) ◽  
pp. 427-436 ◽  
Author(s):  
Kazue Takahashi
Keyword(s):  
Ulf Waves

scholarly journals Multi-point Conjugate Observations of Dayside ULF Waves during an Extended Period of Radial IMF

2020 ◽  
Author(s):  
Xueling Shi ◽  
Michael D. Hartinger ◽  
J. B. H. Baker ◽  
John Michael Ruohoniemi ◽  
Dong Lin ◽  
...  
Keyword(s):  
Extended Period ◽  
Ulf Waves ◽  
Point Conjugate

scholarly journals Modulation of chorus intensity by ULF waves deep in the inner magnetosphere

2016 ◽  
Vol 43 (18) ◽  
pp. 9444-9452 ◽  
Author(s):  
Zhiyang Xia ◽  
Lunjin Chen ◽  
Lei Dai ◽  
Seth G. Claudepierre ◽  
Anthony A. Chan ◽  
...  
Keyword(s):  
Ulf Waves ◽  
Inner Magnetosphere
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