Propagation of whistler mode waves with a modulated frequency in the magnetosphere

Streltsov, A. V.; Gołkowski, M.; Inan, U. S.; Papadopoulos, K.

doi:10.1029/2009ja015155

Cited by 14 publications

(12 citation statements)

References 39 publications

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“…Parameters of the ambient magnetic field, plasma density, and temperature are adopted from Streltsov et al [2010b] where they provide good quantitative agreement between numerical results and observations of VLF waves propagation along the L = 4.9 magnetic field line. In particular, the ambient magnetic field along the L = 4.9 magnetic field line is assumed to be a dipolar: B 0 = B * (1 + 3 sin 2 θ) 1/2 / r 3 , where B * = 31000 nT; θ is a co‐latitudinal angle; and r is a geocentric distance measured in R E = 6371.2 km.…”

Section: Modelmentioning

confidence: 95%

“…The density distribution is modeled as where r 0 = 0.0188; r 1 = 1 + 100/ R E ; r 2 = 1 + 220/ R E ; a 1 = 1 × 10 4 cm −3 ; a 2 = 2.63 × 10 5 cm −3 ; b 1 = a 2 − n * ( r 2 / L ) (with L = 4.9); b 2 = n * / L ; and n * = 129 cm −3 . All these parameters except a 1 are the same as the ones used to model propagation of VLF whistler‐mode waves in the experiment conducted at HAARP [ Streltsov et al , 2010b]. In this study, we use a lower value of a 1 (which describes density in the ionospheric E region) compared with the case considered by Streltsov et al [2010b] (1 × 10 4 vs 7.5 × 10 4 cm −3 ) because we would like to verify that our method is applicable to quiet, nighttime conditions when the ionospheric conductivity is relatively low.…”

Section: Modelmentioning

confidence: 99%

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An alternative method for generation of ULF waves by ionospheric heating

Streltsov

Pedersen

2010

Geophysical Research Letters

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[1] We present results from a numerical study of the generation of ULF waves by the ionospheric feedback instability (IFI) initiated by heating the ionosphere with a powerful HF transmitter. Previous investigations in this area suggested that even a relatively weak modification of the ionospheric conductivity by the heater can initiate IFI and enhance its development, if the heating wave is modulated with a frequency of the most feedback-unstable ULF mode. In this paper, we show that the development of the instability and, as a result, the generation of ULF waves, can be significantly enhanced if the heating spot is moved in the direction of the background electric field with the velocity defined from a simulation of the coupled magnetosphere-ionosphere model.Citation: Streltsov, A. V., and T. R. Pedersen (2010), An alternative method for generation of ULF waves by ionospheric heating,

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Section: Modelmentioning

confidence: 95%

Section: Modelmentioning

confidence: 99%

An alternative method for generation of ULF waves by ionospheric heating

Streltsov

Pedersen

2010

Geophysical Research Letters

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“…Numerical experiments are also useful, even though an amount of computational resources are required in solving a set of Maxwell's equations and the equation of motion of cold plasma, because they can reproduce the wave amplitude variation and the spatial extent of wave packets during their propagation (Streltsov et al 2006(Streltsov et al , 2010(Streltsov et al , 2012. In the present study, we have developed a spatially twodimensional simulation code for the study of the propagation of chorus in the dipole magnetic field.…”

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confidence: 99%

A simulation study of the propagation of whistler-mode chorus in the Earth’s inner magnetosphere

Katoh

2014

Earth Planet Sp

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We study the propagation of whistler-mode chorus in the magnetosphere by a spatially two-dimensional simulation code in the dipole coordinates. We set the simulation system so as to assume the outside of the plasmapause, corresponding to the radial distance from 3.9 to 4.1 R E in the equatorial plane and the latitudinal range from −15 • to +15 • , where R E is the Earth's radius. We assume a model chorus element propagating northward from the magnetic equator of the field line at L = 4 with a rising tone from 0.2 to 0.7 e0 in the time scale of 5,000e0 , where e0 is the electron gyrofrequency at the magnetic equator. For the initial density distribution of cold electrons, we assume three types of initial conditions in the outside of the plasmapause: without a duct (run 1), a density enhancement duct (run 2), and a density decrease duct (run 3). In run 1, the simulation result reveals that whistler-mode waves of the different wave frequencies propagate in the different ray path in the region away from the magnetic equator. In runs 2 and 3, the model chorus element propagates inside the assumed duct with changing wave normal angle. The simulation results show the different propagation properties of the chorus element in runs 2 and 3 and reveal that resultant wave spectra observed along the field line are different between the density enhancement and density decrease duct cases. The spectral modification of chorus by the propagation effect should play a significant role in the interactions between chorus and energetic electrons in the magnetosphere, particularly in the region away from the equator. The present study clarifies that the variation of propagation properties of chorus should be taken into account for the thorough understanding of resonant interactions of chorus with energetic electrons in the inner magnetosphere.

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“…HAARP induced one-hop echoes were observed on DEMETER in the conjugate point (Gołkowski et al, 2011). Additional relavent reports on HAARP wave injection include work by Golkowski et al (2009) and Streltsov et al (2010). A broader review of research efforts at HAARP additionally encapsulating HF wave interactions in the ionosphere has recently been compiled by Streltsov et al (2018).…”

Section: High-frequency Active Auroral Research Program (Haarp)mentioning

confidence: 99%

Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere

Gołkowski

Harid

Hosseini

2019

Front. Astron. Space Sci.

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Controlled experiments involving injection of 0.5 Hz-8 kHz electromagnetic waves into the Earth's magnetosphere have played an important role in discovering and elucidating wave-particle interactions in near-Earth space. Due to the significant engineering challenges of efficiently radiating in the ELF/VLF: 300 Hz-30 kHz band, few experiments have been able to provide sustained transmissions of sufficient power to excite observable effects for scientific studies. Two noteworthy facilities that were successful in generating a large database of pioneering and repeatable observations were the Siple Station Transmitter in Antarctica and the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Both facilities were able to excite Doppler shifted cyclotron resonance interactions leading to linear and non-linear wave amplification, triggering of free running emissions, and pitch angle scattering of energetic electrons. Amplified and triggered waves were primarily observed on the ground in the geomagnetic conjugate region after traversal of the magnetosphere along geomagnetic field aligned propagation paths or in the vicinity of the transmitter following two traversals of the magnetosphere. In several cases, spacecraft observations of the amplified and triggered signals were also made. The observations show the amplifying wave particle interaction to be dynamically sensitive to specific frequency and also specific frequency-time format of the transmitted wave. Transmission of multiple coherent waves closely spaced in frequency showed that the wave particle interaction requires a minimum level of coherency to enter the non-linear regime. Theory and numerical simulations point to cyclotron resonance with counter streaming particles in the 10-100 keV range as the dominant process. A key feature of the non-linear interaction is the phase-trapping of resonant particles by the wave that is believed to drive non-linear wave amplification and the triggering of free-running emissions. Observations and modeling of controlled wave injections have important implications for naturally occurring whistler mode emissions of hiss and chorus and the broader phenomena of radiation belt dynamics. A review of observational, theoretical, and numerical results is presented and suggestions for future studies are made.

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Propagation of whistler mode waves with a modulated frequency in the magnetosphere

Cited by 14 publications

References 39 publications

An alternative method for generation of ULF waves by ionospheric heating

An alternative method for generation of ULF waves by ionospheric heating

A simulation study of the propagation of whistler-mode chorus in the Earth’s inner magnetosphere

Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere

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