Alaska to New Zealand whistler-mode transmission at 6.8 kHz

McPherson, Donald A.; Koons, H. C.; Dazey, M. H.; Dowden, R. L.; Amon, L. E. S.; Thomson, Neil R.

doi:10.1038/248493a0

Cited by 11 publications

(4 citation statements)

References 2 publications

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“…Results from controlled experiments, in which VLF signals transmitted from the ground are used to stimulate equatorial wave generation out to several earth radii, have provided new information concerning the wave/particle and wave/wave interactions which govern wave growth (HELLIWELL and KATSUFRAKIS, 1974;McPHERSON et al, 1974;KOONS and DAZEY, 1974;DOWDEN et al, 1978). These results have given a stimulus to new theoretical work (HELLIWELL and CRYSTAL, 1973;NUNN, 1974;DOWDEN et al, 1978), which in turn has led to a greater un derstanding of the role that relatively weak coherent waves such as PLHR can play in the growth phase of VLF emissions.…”

Section: Introductionmentioning

confidence: 96%

Magnetospheric VLF line radiation observed at Halley, Antarctica

Matthews

Yearby

1981

Planetary and Space Science

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Spectrograms of broad-band ELF/VLF goniometer data obtained from ground based measurements made at Halley, Antarctica (L 0 =4.3, con jugate near St. Anthony, Newfoundland) have shown the presence of discrete line radiation of magnetospheric origin, in the frequency range 1-4 kHz. The properties of this radiation are broadly similar to Power Line Harmonic Radia tion (PLHR), studied from ground based observations made at Siple, Antarc tica (L =4.1, conjugate-Roberval, Quebec), although there are some interesting differences. Line radiation observed at Halley, is never regularly spaced in frequency by 120 Hz, as one may expect if signals from the Newfoundland power distribution system (60 Hz fundamental) are entering the magneto sphere, and being amplified. Instead, frequency spacings are widely distributed about mean values between 50 to 90 Hz. The lines are observed to trigger emissions and often exhibit 2 hop amplitude modulation, which demonstrates that they are of magnetospheric origin. Events occur mostly in quiet to moderate geomagnetic conditions, and during the late af ternoon period of local time. Arrays of lines are often observed to drift upwards together in fre quency. Line bandwidths are 20-30 Hz-much larger than the bandwidths of locally generated induction lines. We show that the line spacing of ,.., 80 Hz is too large to correspond to sideband separation for waves of equatorial field strength ,.., 10 pT, and we investigate the conditions required for effective particle trapping by the wave array, of the type described by NuNN (J. Plasma Phys., 11, 189, 1974). It is proposed that the line radiation either originates in the signals which enter the magnetosphere from Newfoundland, or is 'naturally' generated, possibly by a linear instability which takes place if the electron distribution is unstable in restricted ranges of wave frequency and wave number.

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Section: Introductionmentioning

confidence: 96%

Magnetospheric VLF line radiation observed at Halley, Antarctica

Matthews

Yearby

1981

Planetary and Space Science

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“…band limited white noise, often in the range 3 to 6 kHz. Measurement of magnetospheric amplifica-Hiss is frequently accompanied by whistlers echoing in the tion of special VLF transmissions [McPherson et al, 1974] same path and amplified in the same frequency band [Dowden, indicates that such amplification, and so the duct reflection 1971]. These showed that hiss (also the whistlers appears to be the same from one hop to the next called "VLF noise" at that time) often occurred in isolated so that the resultant hiss intensity is only slowly varying on a bursts lasting an hour or so with a relatively smooth rise and time scale of several minutes.…”

Section: Introductionmentioning

confidence: 99%

“…stant amplitude. Measurement of magnetospheric amplifica-Hiss is frequently accompanied by whistlers echoing in the tion of special VLF transmissions [McPherson et al, 1974] same path and amplified in the same frequency band [Dowden, indicates that such amplification, and so the duct reflection 1971]. Such whistlers were first identified in a series of events loss in the equilibrium case, may occasionally be as high as 30 in which initiating sferics gave rise to long trains of whistlers dB.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal variation of mid‐latitude hiss from six long duration balloon flights

Dowden

Holzworth

1990

J. Geophys. Res.

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The longitudinal variation of mid‐latitude hiss as measured on six balloons at latitudes of 35°S–55°S, shows a significant minimum at 70°E–80°E, about 1000 km east of the geomagnetic conjugate of the Soviet transmitter, UMS (17.1 kHz). It is suggested that the well documented pitch angle diffusion induced by the UMS signal removes the ability of the trapped electrons to maintain the amplification of the hiss to at least the reflection and re‐ducting losses (∼20 dB) at the ends of the echoing, ducted path. The eastward shift of the minimum from the conjugate of UMS is primarily caused by the time taken by the eastward drifting electrons to recover this ability, though the effect is enhanced by the east–west asymmetry in the propagation of hiss under the ionosphere.

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“…( 2) Experiment plan horizontal dipole. (Balloon-supported vertical antennas have been successfully employed in short duration experiments (McPherson et al 1974).) To keep the transmitter power within reasonable bounds (< 100 kW) the horizontal dipole must be erected over low-loss ground, such as a thick ice sheet.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric sciences: Active very low frequency experiments on the magnetosphere from Siple Station, Antarctica

Helliwell

1977

Phil. Trans. R. Soc. Lond. B

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V.l.f. coherent waves transmitted from Siple Station, Antarctica, provide a novel means for the study and control of the magnetosphere and ionosphere. Through cyclotron resonance the waves exchange energy with radiation belt electrons, causing wave growth ( ca. 10 3 in power), wave-wave interaction and modification of the distribution of electrons. The measured growth rates give information on the flux of energetic electrons along the path of propagation. Precipitation induced by v.l.f. waves from lightning, ground transmitters and power grids, alters the ionosphere, affecting propagation (e.l.f., v.l.f., l.f., h.f.) and providing a controlled forcing function for the study of ionospheric processes. The active experiments are supported by the L =4 network of whistler stations in the Antarctic; they provide data on the distribution and movement of the magnetospheric plasma. Both the active and the passive v.l.f. experiments will contribute important data to the I.M.S. (International Magnetospheric Survey) and to the associated space experiments of the I.S.E.E. (International Sun-Earth Explorers) and E.E. (Electrodynamic Explorer) programmes.

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Alaska to New Zealand whistler-mode transmission at 6.8 kHz

Cited by 11 publications

References 2 publications

Magnetospheric VLF line radiation observed at Halley, Antarctica

Magnetospheric VLF line radiation observed at Halley, Antarctica

Longitudinal variation of mid‐latitude hiss from six long duration balloon flights

Atmospheric sciences: Active very low frequency experiments on the magnetosphere from Siple Station, Antarctica

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