Production rates and electron densities in the lower ionosphere due to solar cosmic rays

Adams, Gregory W.; Masley, A. J.

doi:10.1016/0021-9169(65)90029-2

Cited by 55 publications

(18 citation statements)

References 9 publications

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“…More complex methods have also been proposed, involving the derivation of proton flux spectra and the use of ionisation models (e.g. Adams and Masley, 1965). Juday and Adams (1969) determined that the ratio of integral flux to the squared absorption was least sensitive to model proton spectra for a threshold energy of 11 MeV.…”

Section: Introductionmentioning

confidence: 99%

On solar protons and polar cap absorption: constraints on an empirical relationship

et al. 2004

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Abstract.A large database of Solar Proton Events (SPE) from the period 1995 to 2001 is used to investigate the relationship between proton flux at geostationary orbit and Cosmic Noise Absorption (CNA) in the auroral zone. The effect of solar illumination on this relationship is studied in a statistical manner by deriving correlation coefficients of integral flux and absorption as a function of solar zenith angle limit, thus both an upper limit on the angle and the best correlated integral flux of protons are determined (energies in excess of 10 MeV). By considering the correlation of various energy ranges (from the GOES 8 differential proton flux channels) with CNA the range of proton energies for which the relationship between flux and absorption is best defined is established (15 to 44 MeV), thus confirming previous predictions about which proton energy ranges are most effective in giving rise to absorption during Polar Cap Absorption (PCA) events. An empirical relationship between the square root of the integral proton flux and the absorption, measured by the imaging riometer at Kilpisjärvi (IRIS), is determined and departures from linearity and possible causes are examined. Variations in spectral "hardness" and in collision frequency are demonstrated not to be significant causes of the observed departures from a linear relationship. Geomagnetic activity may be a significant factor in changing the relationship between the absorption and the square root of the integral proton flux, although it is concluded that the cause is likely to be more complex than a straightforward dependence on K p . It is suggested that the most significant factor might be a bias in the absorption estimates imposed by the presence of Solar Radio Emission (SRE), which is not routinely measured at the operating frequency of IRIS, making its precise effect difficult to quantify. SRE is known to be most prevalent under conditions of high solar activity, such as those that might give rise to solar proton events.

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Section: Introductionmentioning

confidence: 99%

On solar protons and polar cap absorption: constraints on an empirical relationship

et al. 2004

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“…9. For comparison, the loss rates estimated by ADAMS and MASLEY (1965) and by PARTHASARATHY and RAI (1966) from PCA events, by WHITTEN et al (1965) from the artifitial disturbance induced by a nuclear detonation, and by SMITH et al (1965) from a solar eclipse effect are also shown in the figure. It is surprising that the theoretical result obtained in this paper is seen to be in good agreement with these observational results deduced from the events in which the ionizing sources are certainly quite different from that, assumed in this paper.…”

Section: Ion Composition and Resultant Loss Rate Of Electronsmentioning

confidence: 99%

Theoretical Estimate of the Effective Recombination Coefficient in the D Region

Kono

1972

J. geomagn. geoelec

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“…Riometer observations of integrated absorption have the advantage of yielding long-term synoptic data with relatively little difficulty, but the disadvantage of providing only a height-integrated measurement of the mesosphieric ionization. An estimate of the electron-density profile can be made from multi-frequency rio meter measurements (Parthasarathy et at., 1963), and the results of one such experiment have been combined with satellite observations to produce an effective electron-loss coefficient for the lower ionosphere (Adams and Masley, 1965). Recently, however, more direct measurements of electron-density profiles during PCA events have been carried out at Resolute Bay using the partialreflection technique (Hewitt, 1969), and a combination of measurements of this kind with satellite measurements of proton flux appears to be a potentially valuable source of information on the complex physical and chemical mechanisms of the mesosphere.…”

Section: Diurnal Variation Of Peamentioning

confidence: 99%

Current Problems in Polar-Cap Absorption

Reid

1970

Astrophysics and Space Science Library

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Production rates and electron densities in the lower ionosphere due to solar cosmic rays

Cited by 55 publications

References 9 publications

On solar protons and polar cap absorption: constraints on an empirical relationship

On solar protons and polar cap absorption: constraints on an empirical relationship

Theoretical Estimate of the Effective Recombination Coefficient in the D Region

Current Problems in Polar-Cap Absorption

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