Numerical Simulation of Very-Low-Frequency Waves Passing through the Magnetoactive Plane-Layered Plasma of Earth’s Lower Ionosphere

2020 ◽  
Vol 65 (5) ◽  
pp. 472-479
Author(s):  
A. V. Moshkov ◽  
V. N. Pozhidaev
2019 ◽  
Vol 124 (11) ◽  
pp. 9448-9461 ◽  
Author(s):  
Ajeet K. Maurya ◽  
Morris B. Cohen ◽  
Kondapalli Niranjan Kumar ◽  
D.V. Phanikumar ◽  
Rajesh Singh ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J.-F. Ripoll ◽  
T. Farges ◽  
D. M. Malaspina ◽  
G. S. Cunningham ◽  
E. H. Lay ◽  
...  

AbstractLightning superbolts are the most powerful and rare lightning events with intense optical emission, first identified from space. Superbolt events occurred in 2010-2018 could be localized by extracting the high energy tail of the lightning stroke signals measured by the very low frequency ground stations of the World-Wide Lightning Location Network. Here, we report electromagnetic observations of superbolts from space using Van Allen Probes satellite measurements, and ground measurements, and with two events measured both from ground and space. From burst-triggered measurements, we compute electric and magnetic power spectral density for very low frequency waves driven by superbolts, both on Earth and transmitted into space, demonstrating that superbolts transmit 10-1000 times more powerful very low frequency waves into space than typical strokes and revealing that their extreme nature is observed in space. We find several properties of superbolts that notably differ from most lightning flashes; a more symmetric first ground-wave peak due to a longer rise time, larger peak current, weaker decay of electromagnetic power density in space with distance, and a power mostly confined in the very low frequency range. Their signal is absent in space during day times and is received with a long-time delay on the Van Allen Probes. These results have implications for our understanding of lightning and superbolts, for ionosphere-magnetosphere wave transmission, wave propagation in space, and remote sensing of extreme events.


2015 ◽  
Vol 33 (8) ◽  
pp. 991-995 ◽  
Author(s):  
J. Manninen ◽  
N. G. Kleimenova ◽  
A. Kozlovsky ◽  
I. A. Kornilov ◽  
L. I. Gromova ◽  
...  

Abstract. We investigate a non-typical very low frequency (VLF) 1–4 kHz hiss representing a sequence of separated noise bursts with a strange "mushroom-like" shape in the frequency–time domain, each one lasting several minutes. These strange afternoon VLF emissions were recorded at Kannuslehto (KAN, ϕ = 67.74° N, λ = 26.27° E; L ∼ 5.5) in northern Finland during the late recovery phase of the small magnetic storm on 8 December 2013. The left-hand (LH) polarized 2–3 kHz "mushroom caps" were clearly separated from the right-hand (RH) polarized "mushroom stems" at the frequency of about 1.8–1.9 kHz, which could match the lower ionosphere waveguide cutoff (the first transverse resonance of the Earth–ionosphere cavity). We hypothesize that this VLF burst sequence could be a result of the modulation of the VLF hiss electron–cyclotron instability from the strong Pc5 geomagnetic pulsations observed simultaneously at ground-based stations as well as in the inner magnetosphere by the Time History of Events and Macroscale Interactions during Substorms mission probe (THEMIS-E; ThE). This assumption is confirmed by a similar modulation of the intensity of the energetic (1–10 keV) electrons simultaneously observed by the same ThE spacecraft. In addition, the data of the European Incoherent Scatter Scientific Association (EISCAT) radar at Tromsø show a similar quasi-periodicity in the ratio of the Hall-to-Pedersen conductance, which may be used as a proxy for the energetic particle precipitation enhancement. Our findings suggest that this strange mushroom-like shape of the considered VLF hiss could be a combined mutual effect of the magnetospheric ULF–VLF (ultra low frequency–very low frequency) wave interaction and the ionosphere waveguide propagation.


1998 ◽  
Vol 103 (A6) ◽  
pp. 12023-12035 ◽  
Author(s):  
Naiguo Lin ◽  
P. J. Kellogg ◽  
R. J. MacDowall ◽  
E. E. Scime ◽  
A. Balogh ◽  
...  

2000 ◽  
Vol 18 (12) ◽  
pp. 1613-1622 ◽  
Author(s):  
P. Guio ◽  
S. Børve ◽  
H. L. Pécseli ◽  
J. Trulsen

Abstract. Low frequency electrostatic waves are studied in magnetized plasmas with an electron temperature which varies with position in a direction perpendicular to the magnetic field. For wave frequencies below the ion cyclotron frequency, the waves need not follow any definite dispersion relation. Instead a band of phase velocities is allowed, with a range of variation depending on the maximum and minimum values of the electron temperature. Simple model equations are obtained for the general case which can be solved to give the spatial variation of a harmonically time varying potential. A simple analytical model for the phenomenon is presented and the results are supported by numerical simulations carried out in a 2½-dimensional particle-in-cell numerical simulation. We find that when the electron temperature is striated along B0 and low frequency waves (ω ≪ Ωci) are excited in this environment, then the intensity of these low frequency waves will be striated in a manner following the electron temperature striations. High frequency ion acoustic waves (ω ≫ Ωci) will on the other hand have a spatially more uniform intensity distribution.Key words: Ionosphere (plasma temperature and density) · Radio science (waves in plasma) · Space plasma physics (numerical simulation studies)


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