Whistler‐mode wave interactions with ionospheric plasmas over Arecibo

Abstract

[1] The Naval transmitter, code-named NAU, in Puerto Rico emits radio waves at a power and frequency of 100 kW and 40.75 kHz, respectively. The NAU-generated 40.75 kHz whistler-mode waves are intense enough to excite lower hybrid waves and zero-frequency field-aligned ionospheric irregularities over Arecibo. It is proposed that NAU is responsible for causing the enhanced plasma lines, detected by the Arecibo 430 MHz radar in the nighttime ionosphere F region, in the presence of spread F events. The lower hybrid waves, generated in a broad range of altitudes at the wake of 40.75 kHz whistler-mode waves, have a single frequency of 40.75 kHz but with a spectrum of wavelengths. They can effectively accelerate electrons continuously along the Earth's magnetic field with energies from a fraction of 1 eV to 10 eV. These energetic streaming electrons, when detected by the Arecibo 430 MHz radar, give rise to enhanced plasma lines with a frequency spectrum of $3.25-4.75 MHz.

HF signatures of powerful lightning recorded on DEMETER

“… Liao et al [1989] have also shown that the lightning‐produced VLF waves can cause important modifications in the ionospheric plasma (explosive spread F ) by a parametric instability. Investigating the effect of the VLF transmitter NAU on the ionosphere, Labno et al [2007] found that these powerful VLF waves can propagate along waveguides formed by spread F density perturbations and excite lower hybrid waves which accelerate electrons. It is therefore assumed that the propagation of the HF pulses observed by DEMETER at the times of lightning is due to ionospheric heating by thunderstorm activities below the satellite.…”

Explaining polarization reversals in STEREO wave data

“…Excited lower hybrid waves have also been linked to explosive spread F above thunderstorms by Baker et al [2000]. Lower hybrid waves attributed to the parametric decay mechanism of Lee and Kuo [1984] have been shown to be the cause of explosive spread F occurrence at equatorial latitudes over Jicamarca (Peru) [ Liao et al , 1989] and Aricebo (Puerto Rico) [ Labno et al , 2007]. The observations presented in this Paper show that this parametric decay mechanism also operates over the NPM transmitter.…”

“…Thus the purely growing mode will be observed to have a finite frequency and the lower hybrid waves will be symmetric about the incident whistler mode wave frequency. This process has been invoked to explain various observations in the upper ionosphere [ Labno et al , 2007; Dalkir et al , 1992; Liao et al , 1989; Groves et al , 1988] where anthropogenic transmitter waves are above the threshold for growth of this instability.…”

Modeling Phenotypes of Tuberous Sclerosis in the Mouse

“…Lower hybrid waves and field-aligned zero-frequency plasma density irregularities can be parametrically excited in the ionosphere [Lee and Kuo, 1984]. The excited ionospheric density irregularities have scale sizes ranging from a fraction of 1 meter to 10 meters and align with geomagnetic field lines to form filaments [Labno et al, 2007]. The lower hybrid waves can accelerate electrons and ions along and across the geomagnetic field, respectively, generating non-Maxwellian distribution functions [Lynch et al,1994] capable of exciting airglow.…”

“…The intriguing phenomena reported here include large-scale turbulence created by tsunami-launched acoustic gravity waves [Lee et al, 2008] and relatively short-scale turbulence generated by VLF waves injected from ground-based transmitters [Labno et al, 2007]. In the first part of the report we present measurements of ionospheric plasma dynamics conducted at the Arecibo Observatory between 20:00 and 24:00 local time (LT) on December 25 and 26, 2004 using the 430 MHz incoherent scatter radar (ISR) supported by data from two nearby ionosondes and Global Positioning System (GPS) satellites.…”