Performance of VLF, LF, and MF telecommunication systems in a simulated satellite power system environment ascertained by experimental means

Rush, C. M.; Violette, E. J.; Espeland, R H; Carroll, J. C.; Allen, Kenneth C.

doi:10.1029/rs016i002p00219

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Nevertheless, shifts in our observed spectra can be compared by using the proportional relationship above. The Platteville antenna description in the work by Rush et al [1981] and the transmitter operating logs show that the power densities during the experiment were nearly the same for 6.2-MHz and 9.9-MHz heating, at a level of about 65 #W/m 2. Thus we should expect a threshold irregularity shift off-3/2, or about a factor of 2, between 6.2-MHz and 9.9-MHz heating.…”

Section: Overdense Heatingmentioning

confidence: 88%

Heater‐generated intermediate‐scale irregularities: Spatial distribution and spectral characteristics

Livingston¹

1983

Radio Science

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The first extensive phase scintillation measurements during both overdense and underdense heating at Platteville, Colorado, are described. The data were collected from an aircraft making repeated scans in the vicinity of the heated volume, to establish the overall spatial distribution of intermediate‐scale irregularities. During overdense heating, the irregularities maximize in strength near the HF reflection height, and map downward at least 100 km with only moderate weakening. From the relative frequency shifts of the phase spectra measured for different directions of aircraft motion, the irregularity anisotropy and drift have also been estimated. The change in phase spectral shape between 6.2‐MHz and 9.9‐MHz overdense heating is consistent with thermal self‐focusing irregularity generation. Underdense heating produces a different phase spectral signature than is theoretically predicted, although enhanced energy does occur at scintillation‐producing scale sizes.

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Section: Overdense Heatingmentioning

confidence: 88%

Heater‐generated intermediate‐scale irregularities: Spatial distribution and spectral characteristics

Livingston¹

1983

Radio Science

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“…A series of HF ionospheric heating experiments were conducted using the Platteville, Colorado, highpower HF transmitter facility in the months of August, September, and October 1979. The facility was used to simulate the effects of SPS ionospheric heating while the performances of ¾LF, LF, and MF telecommunication systems were monitored [Rush et al, 1981]. At the same time, cross-modulation and ionosonde experiments were also conducted to verify that the ionosphere was being modified.…”

Section: Hf Heating Experiments and Measurementsmentioning

confidence: 99%

Simulation of D and E region high‐power microwave heating with HF ionospheric modification experiments

Meltz¹,

Rush²,

Violette³

1982

Radio Science

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Fluid and kinetic theory calculations predict that the microwave beam from a solar power satellite could be intense enough to cause large, but localized changes in the properties of the lower ionosphere by ohmic heating. A 5-GW system, radiating a peak flux of 23 mW/cm 2 at a frequency of 2.45 GHz, could raise the electron temperature by a factor of 2-3, increase the E region density by 10-20%, and cause up to a 50ø/,, reduction in the D layer electron concentration. Doubling the flux could lead to a fivefold temperature rise and a 40ø/,, increase in the E region density. Since power is absorbed from the beam and heats the ionosphere at a rate that is proportional to the ratio of the flux to the square of an effective frequency, the effects of microwave heating can be studied at much lower power fluxes with high-frequency radio waves. To investigate these effects, a series of ionospheric heating experiments were conducted at Platteville, Colorado, using the high-frequency, high-power facility. A pulsed ionosonde probe, located below the most intense portion of the high-power beam, was used to observe the changes in the D and lower E regions. Phase and amplitude measurements were recorded during both CW and pulsed heating. Prompt (less than 50 ms) and sustained changes were observed in both the phase and attenuation. Perhaps most interesting are the large phase variations of several cycles at 3.4 MHz that were seen following turn-on and turn-off of a 5.2-MHz heating wave. These changes occur relatively slowly, but steadily, in about 60-90 s. The observed changes in the probe amplitude and phase have been compared with theoretical estimates derived by integrating the coupled equations for power flux, electron temperature, and density as a function of altitude and time for both time-varying and steady heating fluxes. The agreement is generally close, considering the differences between the ambient electron density model and the actual distributions. within the beam and its cross-sectional dimensions are key design parameters since they determine the size of the receiving antenna and the total amount of power that can be delivered by a single system [Kraft and Piland, 1980]. The maximum flux and the size of the beam will also determine to what extent, if any, the ionosphere will be changed by operation of the system.As a result of a number of system definition studies [Koomanoff and $andahl, 1980], a 2450-MHz, 5-GW reference system design has evolved which typifies a technologically plausible approach. Early in the course of developing this design, a limit of 23 mW/cm 2 was set for the peak flux on the grounds that radio wave fluxes producing comparable ohmic heating were observed to cause significant changes in the D, E, and F regions of the ionosphere [Utlaut and Cohen, 1971]. Of principal concern was the expectation that larger fluxes would substantially modify the electron density distribution and disrupt or degrade telecommunications systems whose radio signals passed through the region of the ionosphere illumin...

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Effect of local ionospheric inhomogeneity on the field of a vertical electric dipole

Solov'ev¹

1985

Radiophys Quantum Electron

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Performance of VLF, LF, and MF telecommunication systems in a simulated satellite power system environment ascertained by experimental means

Cited by 3 publications

References 14 publications

Heater‐generated intermediate‐scale irregularities: Spatial distribution and spectral characteristics

Heater‐generated intermediate‐scale irregularities: Spatial distribution and spectral characteristics

Simulation of D and E region high‐power microwave heating with HF ionospheric modification experiments

Effect of local ionospheric inhomogeneity on the field of a vertical electric dipole

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