The effect of an ionospheric inhomogeneity on magnetic pulsation polarization

Belova, Evgenia; Pchelkina, E.; Lyatsky, W.; Pashin, A. B.

doi:10.1016/s1364-6826(96)00182-4

Cited by 2 publications

(1 citation statement)

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“… Fujita and Tamao [1988] did not include such conductivity effect related to the proton precipitation in their model calculation. Belova et al [1997]showed by a model calculation of the polarization characteristics of the geomagnetic pulsation that the polarization ellipse will rotate along the inhomogeneity of ionospheric conductivity. However, we do not know how the non‐uniform conductivities affect the Pc1 polarization when they exist at the same location as the Pc1 ionospheric source.…”

Section: Discussionmentioning

confidence: 99%

Polarization of Pc1/EMIC waves and related proton auroras observed at subauroral latitudes

Nomura¹,

Shiokawa²,

Sakaguchi³

et al. 2012

J. Geophys. Res.

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[1] We have investigated the polarization of Pc1 geomagnetic pulsations and related proton auroras at subauroral latitudes, using an induction magnetometer and an all-sky camera at Athabasca, Canada (54.7°N, 246.7°E, magnetic latitude (mlat) 61.7°N). Isolated proton auroras often appear in association with Pc1 pulsations, because of proton scattering by electromagnetic ion cyclotron (EMIC) waves in the magnetosphere. We used the proton aurora as a proxy for the location and size of the Pc1 ionospheric source. For 27 Pc1 events with simultaneously observed proton auroras over 4 years from September 7, 2005 to September 6, 2009, we calculated the distances between the Pc1 ionospheric source and the observation site, normalized by the scale size of the source. We tried three different definitions of the scale size of Pc1 ionospheric source to calculate the normalized distances. We found that the rotation angle q between the Pc1 polarization ellipse and the direction to the proton aurora changes from 90°to 0°as the normalized distance increases. For the definition of the scale sizes that gives most clear q-transition from 90°to 0°, the transition occurs at the normalized distance $2.0-4.0, while it was $1.0-2.0 by the model calculation of Fujita and Tamao (1988). The averaged major axes tend to point toward the proton aurora at larger distances. The difference of the transition location may imply that the Pc1 ionospheric sources are larger than the isolated proton auroras, or that the inhomogenuity of the ionospheric conductivity by the proton precipitation affects the transition distances.

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Section: Discussionmentioning

confidence: 99%