scholarly journals Magnetospheric injection of ELF/VLF waves with modulated or steered HF heating of the lower ionosphere

2011 ◽  
Vol 116 (A6) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. B. Cohen ◽  
U. S. Inan ◽  
D. Piddyachiy ◽  
N. G. Lehtinen ◽  
M. Gołkowski
Keyword(s):  
Lower Ionosphere ◽  
Hf Heating ◽  
Vlf Waves

scholarly journals Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

2004 ◽  
Vol 22 (7) ◽  
pp. 2643-2653 ◽  
Author(s):  
M. Platino ◽  
U. S. Inan ◽  
T. F. Bell ◽  
J. Pickett ◽  
E. J. Kennedy ◽  
...  
Keyword(s):  
High Frequency ◽  
Lower Ionosphere ◽  
Spectral Signature ◽  
Closed Field ◽  
Ionospheric Heating ◽  
Higher Power ◽  
Power Operation ◽  
Field Lines ◽  
Vlf Waves

Abstract. It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere illuminated by the ELF/VLF waves. In an attempt to investigate this question further, ground-satellite conjunction experiments have recently been conducted using the four Cluster satellites and the HF heater of the High-Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska. Being located on largely closed field lines at L≈4.9, HAARP is currently also being used for ground-to-ground type of ELF/VLF wave-injection experiments, and will be increasingly used for this purpose as it is now being upgraded for higher power operation. In this paper, we describe the HAARP installation and present recent results of the HAARP-Cluster experiments. We give an overview of the detected ELF/VLF signals at Cluster, and a possible explanation of the spectral signature detected, as well as the determination of the location of the point of injection of the HAARP ELF/VLF signals into the magnetosphere using ray tracing.

VLF-HF heating of the lower ionosphere and ELF wave generation

1992 ◽  
Vol 19 (4) ◽  
pp. 61-64 ◽  
Author(s):  
Y. N. Taranenko ◽  
U. S. Inan ◽  
T. F. Bell
Keyword(s):  
Lower Ionosphere ◽  
Wave Generation ◽  
Hf Heating

scholarly journals ELF wave generation in the ionosphere using pulse modulated HF heating: initial tests of a technique for increasing ELF wave generation efficiency

1999 ◽  
Vol 17 (6) ◽  
pp. 759-769 ◽  
Author(s):  
R. Barr ◽  
P. Stubbe ◽  
M. T. Rietveld
Keyword(s):  
Fundamental Frequency ◽  
Lower Ionosphere ◽  
Wave Generation ◽  
Cooling Time ◽  
Ionospheric Currents ◽  
Time Constants ◽  
Radio Science ◽  
Heating And Cooling ◽  
Hf Heating ◽  
Even Harmonics

Abstract. This paper describes the results of a preliminary study to determine the effective heating and cooling time constants of ionospheric currents in a simulated modulated HF heating, `beam painting' configuration. It has been found that even and odd harmonics of the fundamental ELF wave used to amplitude modulate the HF heater are sourced from different regions of the ionosphere which support significantly different heating and cooling time constants. The fundamental frequency and its odd harmonics are sourced in a region of the ionosphere where the heating and cooling time constants are about equal. The even harmonics on the other hand are sourced from regions of the ionosphere characterised by ratios of cooling to heating time constant greater than ten. It is thought that the even harmonics are sourced in the lower ionosphere (around 65 km) where the currents are much smaller than at the higher altitudes around 78 km where the currents at the fundamental frequency and odd harmonics maximise.Key words. Electromagnetics (antennae) · Ionosphere (active experiments) · Radio science (non linear phenomena)

Analysis of the nighttime lower ionosphere by monitoring VLF waves propagation in Antarctic

2021 ◽  
Author(s):  
Jorge Samanes ◽  
Jose Gamonal ◽  
Emilia Correia ◽  
Ricardo Y. C. Cueva
Keyword(s):  
Lower Ionosphere ◽  
Waves Propagation ◽  
Vlf Waves

scholarly journals Excitation of Alfvén waves by modulated HF heating of the ionosphere, with application to FAST observations

2002 ◽  
Vol 20 (1) ◽  
pp. 57-67 ◽  
Author(s):  
E. Kolesnikova ◽  
T. R. Robinson ◽  
J. A. Davies ◽  
D. M. Wright ◽  
M. Lester
Keyword(s):  
Electric Field ◽  
Scalar Potential ◽  
Lower Ionosphere ◽  
Alfven Wave ◽  
Thermal Electron ◽  
Strong Electron ◽  
Inner Magnetosphere ◽  
Hf Heating ◽  
Parallel Current ◽  
Current Electric Field

Abstract. During the operation of the EISCAT high power facility (heater) at Tromsø, Norway, on 8 October 1998, the FAST spacecraft made electric field and particle observations in the inner magnetosphere at 0.39 Earth radii above the heated ionospheric region. Measurements of the direct current electric field clearly exhibit oscillations with a frequency close to the modulated frequency of heater ( ~ 3 Hz) and an amplitude of ~ 2 - 5 mV m-1. Thermal electron data from the electrostatic analyser show the modulation at the same frequency of the downward electron fluxes. During this period the EISCAT UHF incoherent scatter radar, sited also at Tromsø, measured a significant enhancement of the electron density in E-layer up to 2 · 1012 m-3. These observations have prompted us to make quantitative estimates of the expected pulsations in the inner magnetosphere caused by the modulated HF heating of lower ionosphere. Under the conditions of the strong electron precipitation in the ionosphere, which took place during the FAST observations, the primary current caused by the perturbation of the conductivity in the heated region is closed entirely by the parallel current which leaks into the magnetosphere. In such circumstances the conditions at the ionosphere-magnetosphere boundary are most favourable for the launching of an Alfvén wave: it is launched from the node in the gradient of the scalar potential which is proportional to the parallel current. The parallel electric field of the Alfvén wave is significant in the region where the electron inertial length is of order of the transverse wavelength of the Alfvén wave or larger and may effectively accelerate superthermal electrons downward into the ionosphere.Key words. Ionosphere (active experiments; ionosphere – magnetosphere interactions; particle acceleration)

scholarly journals Saturation effects of the lower ionosphere based on two‐dimensional HF heating model

2017 ◽  
Vol 122 (1) ◽  
pp. 874-890 ◽  
Author(s):  
Qi Cheng ◽  
Li‐xin Guo ◽  
Hui‐min Li ◽  
Jiang‐ting Li
Keyword(s):  
Lower Ionosphere ◽  
Two Dimensional ◽  
Heating Model ◽  
Hf Heating ◽  
Saturation Effects

The polarization characteristics of ELF/VLF waves generated via HF heating experiments of the ionosphere by EISCAT

2018 ◽  
Vol 25 (9) ◽  
pp. 092902 ◽  
Author(s):  
Jutao Yang ◽  
Qingliang Li ◽  
Jianguo Wang ◽  
Shuji Hao ◽  
Guanglin Ma
Keyword(s):  
Polarization Characteristics ◽  
Hf Heating ◽  
Vlf Waves
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