Micropulsations observed by whistler-mode transmissions

Rietveld, M. T.; Dowden, R. L.; Amon, L. E. S.

doi:10.1038/276165a0

Cited by 10 publications

(5 citation statements)

References 9 publications

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“…Except for these :differences, both approaches are comparable. [1977], Rietveld et al [1978], and this report all support the proposal that hydromagnetic waves affect VLF propagation in whistler mode ducts. The radial magnetic field motions induced by the HM waves change the phase delay of the VLF signals.…”

Section: Rietveld Et Al [1978] Reported Correlations Between Pcsupporting

confidence: 80%

“…Unfortunately, the time resolution of his measurements was insufficient to observe any delay between VLF phase path changes and magnetic field changes. Rietveld et al [1978] reported correlations between whistler mode signals and magnetic pulsations similar to those discussed here. They used signals at 6.6 kHz from a transportable VLF transmitter in Alaska as received in Dunedin, New Zealand (oe = 2.7).…”

Section: Short-term Variationssupporting

confidence: 80%

“…(The south-moving disturbance has the same shaped field, though the negative bz bump reaches the southern ionosphere first., of course. In Figure 5 there appears to be little if any pul-Comparison With Other Studies o.f VLF Phase and Magnetic Pulsations As mentioned in Section 1, there are two other studies which have compared short-term variations in phase delay and magnetic pulsations,Andrews [1977] andRietveld et al [1978] Andrews [1977]. was the first to demonstrate the connection between the two.…”

mentioning

confidence: 83%

“…There are two main differences between their approach and ours. First, the signals analyzed by Rietveld et al [1978] showed nonlinear amplification (i.e., growth with phase advance) just before the first interval they studied, though not during that interval. Two-tone transmission was not used; its growth-suppression effect had not yet been discovered.…”

Section: Rietveld Et Al [1978] Reported Correlations Between Pcmentioning

confidence: 99%

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Correlation of whistler mode phase delay with transient hydromagnetic waves

Paschal¹,

Lanzerotti²,

Maclennan³

1990

J. Geophys. Res.

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Changes in the phase delay of a ducted whistler mode signal from the Siple Station VLF transmitter to a receiver at Roberval, Quebec, are compared to variations in the horizontal components of the Earth's magnetic field measured nearby at La Tuque, Quebec. The VLF transmission contains 10.5 min of two distinct tones with 30‐Hz separation. Each tone suppresses the cyclotron‐resonance growth of the other, eliminating growth‐associated phase effects, and allows phase changes due to radial duct motion to be observed. Spectrograms of the VLF phase delay and variations in the components of the geomagnetic field show similar features, with phase features preceding magnetic features by 20 to 30 s. A cross‐correlation plot of VLF phase delay and variations in the east–west component shows a bipolar signature which is interpreted as evidence of transient hydromagnetic waves in the 20–45 s band (Pc 3 band) moving from equator to ground. Previous studies have noted correlations between VLF Doppler shifts and resonant hydromagnetic waves, but this is the first report where the VLF phase delay is used directly, and where resolution is sufficient to observe a transient hydromagnetic wave which has a parallel wavelength shorter than the length of the field line.

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Section: Rietveld Et Al [1978] Reported Correlations Between Pcsupporting

confidence: 80%

Section: Short-term Variationssupporting

confidence: 80%

mentioning

confidence: 83%

Section: Rietveld Et Al [1978] Reported Correlations Between Pcmentioning

confidence: 99%

See 2 more Smart Citations

Correlation of whistler mode phase delay with transient hydromagnetic waves

Paschal¹,

Lanzerotti²,

Maclennan³

1990

J. Geophys. Res.

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“…While the spectral characteristics of these signals have been known for many years, most studies have examined only signal amplitudes versus frequency and time and have not considered the signal's phase. Recent work has begun to include phase analysis [Paschal, 1988;Paschal and Helliwell, 1984;Dowden et al, 1978;Rietveld et al, 1978;Rietveld, 1980] Paschal and Helliwell [1984] noted that only those by Nunn [1974], Dowden et al [1978], and Helliwell and Inan [1982] discuss the phase behavior. Each of these results appear to be consistent with the general phase advance during the growth of a transmitted pulse.…”

Section: Introductionmentioning

confidence: 99%

Space‐time evolution of whistler mode wave growth in the magnetosphere

Carlson¹,

Helliwell²,

Inan³

1990

J. Geophys. Res.

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A new model is developed to simulate the space‐time evolution of a propagating coherent whistler mode wave pulse in the magnetosphere. The model is applied to the case of single frequency (2–6 kHz) wave pulses injected into the magnetosphere near L ≃ 4, using the VLF transmitting facility at Siple Station, Antarctica. The mechanism for growth is cyclotron resonance between the circularly polarized waves and the gyrating energetic electrons of the radiation belts. Application of this model reproduces observed exponential wave growth up to a saturated level. Additionally, the model predicts the observed initial linear increase in the output frequency versus time. This is the first time these features have been reproduced using applied wave intensities small enough to be consistent with satellite measurements. The center velocities of the electrons entering the wave pulse are selected in a way which maximizes the growth rate. The results show the importance of the transient aspects in the wave growth process. The growth established as the wave propagates toward the geomagnetic equator results in a spatially advancing wave phase structure due mainly to the geomagnetic inhomogeneity. Through the feedback of this radiation upon other electrons, conditions are established which result in a linearly increasing output frequency with time.

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Limiting wave growth for electron cyclotron waves

Singh¹,

Singh

1994

Earth Moon Planet

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Micropulsations observed by whistler-mode transmissions

Cited by 10 publications

References 9 publications

Correlation of whistler mode phase delay with transient hydromagnetic waves

Correlation of whistler mode phase delay with transient hydromagnetic waves

Space‐time evolution of whistler mode wave growth in the magnetosphere

Limiting wave growth for electron cyclotron waves

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