Characteristics of Rising Tone Whistler Mode Waves Inside the Earth's Plasmasphere, Plasmaspheric Plumes, and Plasmatrough

Teng, Shang‐Hua; Li, W.; Tao, X.; Shen, Xue; Ma, Q.

doi:10.1029/2019gl083372

Cited by 9 publications

(11 citation statements)

References 78 publications

(116 reference statements)

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“…A coherent relatively large amplitude LF (and HF) hiss were detected in plasma plumes (L > 7). Hiss inside plumes have been reported previously (Shi et al, ; Summers et al, ; Teng et al, ; Tsurutani et al, ). We argue that because plumes are relatively small regions of space, the Thorne et al () mechanism of circulation of local plasmaspheric hiss with multiple passages through the generation region will not be applicable.…”

Section: Discussionsupporting

confidence: 72%

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Low Frequency (f < 200 Hz) Polar Plasmaspheric Hiss: Coherent and Intense

et al. 2019

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Low frequency (LF)~22 Hz to 200 Hz plasmaspheric hiss was studied using a year of Polar plasma wave data occurring during solar cycle minimum. The waves are found to be most intense in the noon and early dusk sectors. When only the most intense LF (ILF) hiss was examined, they are found to be substorm dependent and most prominent in the noon sector. The noon sector ILF waves were also determined to be independent of solar wind ram pressure. The ILF hiss intensity is independent of magnetic latitude. ILF hiss is found to be highly coherent in nature. ILF hiss propagates at all angles relative to the ambient magnetic field. Circular, elliptical, and linear/highly elliptically polarized hiss have been detected, with elliptical polarization the dominant characteristic. A case of linear polarized ILF hiss that occurred deep in the plasmasphere during geomagnetic quiet was noted. The waveforms and polarizations of ILF hiss are similar to those of intense high frequency hiss. We propose the hypothesis that~10-100 keV substorm injected electrons gradient drift to dayside minimum B pockets close to the magnetopause to generate LF chorus. The closeness of this chorus to low altitude entry points into the plasmasphere will minimize wave damping and allow intense noon-sector ILF hiss. The coherency of ILF hiss leads the authors to predict energetic electron precipitation into the mid latitude ionosphere and the electron slot formation during substorms. Several means of testing the above hypotheses are discussed.

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Section: Discussionsupporting

confidence: 72%

“…Circulation models cannot be applied for such small regions of space. Recent works on hiss within plumes (Hartley et al, 2019;Li et al, 2019;Nakamura et al, 2018;Shi et al, 2019;Teng et al, 2019;Zhang et al, 2018), although not the main focus of this paper, will be commented on in sections 4 and 5 of this paper in this light.…”

Section: Introductionmentioning

confidence: 99%

Low Frequency (f < 200 Hz) Polar Plasmaspheric Hiss: Coherent and Intense

et al. 2019

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“…Whistler mode waves are often observed in plasmaspheric plumes (Chan & Holzer, 1976; Hayakawa et al, 1986; Li et al, 2019; Shi et al, 2019; Su et al, 2018; Tsurutani et al, 2015), which are composed of plasma being drained from the reservoir of plasmaspheric plasma and extending into the more tenuous outer magnetosphere (Chen & Wolf, 1972; Elphic et al, 1996; Goldstein et al, 2004; Grebowsky, 1970; Weiss et al, 1997). Whistler mode waves in plumes are found to exhibit broadband emissions or discrete rising tones (Nakamura et al, 2018; Shi et al, 2019; Su et al, 2018; Teng et al, 2019) and typically have stronger wave amplitudes, up to 1.5 nT (Su et al, 2018) than typical plasmaspheric hiss (Shi et al, 2019). Due to larger wave amplitudes and higher ratio of plasma to electron cyclotron frequency in plumes (compared to plasmasphere or plasmasheet), pitch angle scattering loss driven by whistler mode waves in plumes could be stronger than plasmaspheric hiss, particularly at lower energy (W. Li et al, 2019), suggesting their potential importance in energetic electron loss process (e.g., Summers et al, 2008; W. Zhang, Fu, et al, 2018).…”

Section: Local Energy and Pitch Angle Scatteringmentioning

confidence: 99%

Earth's Van Allen Radiation Belts: From Discovery to the Van Allen Probes Era

2019

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Discovery of the Earth's Van Allen radiation belts by instruments flown on Explorer 1 in 1958 was the first major discovery of the Space Age. The observation of distinct inner and outer zones of trapped megaelectron volt (MeV) particles, primarily protons at low altitude and electrons at high altitude, led to early models for source and loss mechanisms including Cosmic Ray Albedo Neutron Decay for inner zone protons, radial diffusion for outer zone electrons and loss to the atmosphere due to pitch angle scattering. This scattering lowers the mirror altitude for particles in their bounce motion parallel to the Earth's magnetic field until they suffer collisional loss. A view of the belts as quasi‐static inner and outer zones of energetic particles with different sources was modified by observations made during the Solar Cycle 22 maximum in solar activity over 1989–1991. The dynamic variability of outer zone electrons was measured by the Combined Radiation Release and Effects Satellite launched in July 1990. This variability is caused by distinct types of heliospheric structure that vary with the solar cycle. The launch of the twin Van Allen Probes in August 2012 has provided much longer and more comprehensive measurements during the declining phase of Solar Cycle 24. Roughly half of moderate geomagnetic storms, determined by intensity of the ring current carried mostly by protons at hundreds of kiloelectron volts, produce an increase in trapped relativistic electron flux in the outer zone. Mechanisms for accelerating electrons of hundreds of electron volts stored in the tail region of the magnetosphere to MeVenergies in the trapping region are described in this review: prompt and diffusive radial transport and local acceleration driven by magnetospheric waves. Such waves also produce pitch angle scattering loss, as does outward radial transport, enhanced when the magnetosphere is compressed. While quasilinear simulations have been used to successfully reproduce many essential features of the radiation belt particle dynamics, nonlinear wave‐particle interactions are found to be potentially important for causing more rapid particle acceleration or precipitation. The findings on the fundamental physics of the Van Allen radiation belts potentially provide insights into understanding energetic particle dynamics at other magnetized planets in the solar system, exoplanets throughout the universe, and in astrophysical and laboratory plasmas. Computational radiation belt models have improved dramatically, particularly in the Van Allen Probes era, and assimilative forecasting of the state of the radiation belts has become more feasible. Moreover, machine learning techniques have been developed to specify and predict the state of the Van Allen radiation belts. Given the potential Space Weather impact of radiation belt variability on technological systems, these new radiation belt models are expected to play a critical role in our technological society in the future as much as meteorological models do today.

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“…Generally, Chorus wave is considered to be excited through the cyclotron resonance with anisotropic energetic electrons near the magnetic equator outside the plasmasphere (H. Li et al., 2016a; W. Li et al., 2009b, Tang et al., 2014; Tang & Summers, 2019, Zhang et al., 2020; Summers & Tang, 2021). They are primarily distributed outside the plasmasphere on the dawn side (Teng et al., 2018a; Teng et al., 2019). Previous research has suggested that strong chorus in the frequency range 200 < f < 2,000 Hz can extend to higher magnetic latitudes under active conditions (Meredith et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Influence of Solar Wind Dynamic Pressure on Distribution of Whistler Mode Waves Based on Van Allen Probe Observations

Tang

Yuan

et al. 2023

JGR Space Physics

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In this study, the effect of solar wind dynamic pressure (PSW) on the global distribution of whistler mode waves (including chorus and hiss waves) while the absence of substorm activity is investigated using the data originating from the Van Allen Probes for nearly 5 years. After the effect of substorm activity is excluded, our statistical results indicate that the hiss and chorus waves exhibit different characteristics with the increase of PSW. The amplitudes of chorus waves increase on the dayside with the PSW strengthen, which can be explained through the local enhanced electron temperature anisotropy and more intense emission for the chorus in the inner magnetosphere. Interestingly, the amplitudes of hiss wave are reduced with the increase of PSW. The weakness of hiss waves can be attributed to electrons at high L‐shells which drift out of the magnetosphere on the dayside when the magnetopause's position decreases. It can significantly result in a reduced chorus inside the magnetopause that will evolve into hiss waves. In addition, the upper and lower cutoff frequencies of hiss waves will increase. This new finding is critical for understanding the generation and evolution of whistler mode waves and its responses to the intensity of PSW.

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Characteristics of Rising Tone Whistler Mode Waves Inside the Earth's Plasmasphere, Plasmaspheric Plumes, and Plasmatrough

Cited by 9 publications

References 78 publications

Low Frequency (f < 200 Hz) Polar Plasmaspheric Hiss: Coherent and Intense

Low Frequency (f < 200 Hz) Polar Plasmaspheric Hiss: Coherent and Intense

Earth's Van Allen Radiation Belts: From Discovery to the Van Allen Probes Era

Influence of Solar Wind Dynamic Pressure on Distribution of Whistler Mode Waves Based on Van Allen Probe Observations

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