The influence of the interplanetary medium on SuperDARN radar scattering occurrence

Ballatore, P.; Villain, J. P.; Vilmer, Nicole; Pick, M.

doi:10.1007/s005850000303

Cited by 7 publications

(23 citation statements)

References 13 publications

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“…This delay is set equal to 1 hour because this value optimizes the correlation between ground‐based and interplanetary measurements in our data set. In addition, the approximation of a 1‐hour delay is in agreement with previous estimations of average delays between satellites and ground‐based measurements [e.g., Arnoldy , 1971; Ballatore et al , 2001]. The results that we obtain with this average delay are qualitatively similar to the results obtained with a slightly different delay or, in particular, to the results obtained with a more accurate calculation of the delays at specific times.…”

Section: Data Analysis and Experimental Observationssupporting

confidence: 90%

Effects of fast and slow solar wind on the correlations between interplanetary medium and geomagnetic activity

Ballatore¹

2002

Journal of Geophysical Research: Space Physics

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[1] The coupling between interplanetary parameters and geomagnetic activity has been investigated. In particular, the correlations between the interplanetary medium and the geomagnetic indices Kp and Dst have been calculated for different ranges of solar wind speed. The correlation coefficients obtained for data points corresponding to solar wind slower than 550 km/s are equal or slightly higher than the global correlations. The observations show generally lower correlation coefficients for solar wind speeds faster than 550 km/s. These results suggest that at high solar wind speeds the processes responsible for the energy transfer between the interplanetary medium and the magnetosphere saturate. In addition, the influence of internal magnetospheric plasma physics on the geomagnetic activity may be larger for the faster solar wind intervals. In the context of the deterministically chaotic approximations we discuss how the threshold at $550 km/s might represent the break of the order in the interplanetary-geomagnetic coupling system, so that the linear correlations or the correlations with a relatively weak departure from linearity are significant mostly during the slower solar wind.

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Section: Data Analysis and Experimental Observationssupporting

confidence: 90%

Effects of fast and slow solar wind on the correlations between interplanetary medium and geomagnetic activity

Ballatore¹

2002

Journal of Geophysical Research: Space Physics

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“…They concluded that the ionospheric electron density controls the onset of echoes at a specific range, thus advocating refraction as a key factor for echo detection. Ballatore et al [2001] found that there is a statistically significant correlation between Northern Hemisphere radar echo occurrence and negative interplanetary magnetic field B z values, independent of season. Parkinson et al [2003] considered 1 year (1999)(2000) of echo statistics for the Australian SuperDARN radar and noticed a March (autumn) maximum, though the overall seasonal variation was, apparently, not significant.…”

Section: Review Of Previous Hf Studiesmentioning

confidence: 83%

“…Ballatore et al . [] found that there is a statistically significant correlation between Northern Hemisphere radar echo occurrence and negative interplanetary magnetic field B z values, independent of season. Parkinson et al .…”

Section: Review Of Previous Hf Studiesmentioning

confidence: 98%

Seasonal and diurnal variations of PolarDARN F region echo occurrence in the polar cap and their causes

et al. 2014

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F region echo occurrence rates for the Polar Dual Auroral Radar Network (PolarDARN) HF radars at Inuvik (INV), Rankin Inlet (RKN), and Clyde River (CLY) are compared for observations in 2013. The CLY radar shows somewhat smaller echo occurrence rates consistent with its more poleward geographic and geomagnetic location. For all three radars, the winter occurrence rates are roughly twice that of the corresponding summer rates. For observations in the midnight sector, strong equinoctial maxima are evident. In terms of season and local time, echo occurrence patterns are found to be roughly the same for all radars: seasonally, clear maxima are found near noon during both winter and summer, while, diurnally, enhancements are found during equinoctial dusk. A comparison of data from roughly the same scattering area shows that having strong electron density in the scattering volume is not sufficient for getting an HF echo: propagation conditions along the propagation path are also important. Diurnal variations in the F region electron density and electric field (both measured by Canadian Advanced Digital Ionosonde) are compared to those of RKN echo occurrence rates for observations over Resolute Bay (RB) located at a geomagnetic latitude of 83°N. These results show a reasonable correlation between occurrence and electron density for both winter and summer periods and correlation between occurrence and electric field during summer periods.

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“…The IMF variations have been previously shown to affect HF radar observations of the auroral ionosphere in both the F region [ Ballatore et al , ] and E region [ Makarevich et al , ]. The IMF variations are a consequence of solar activity and are not related to the time of day or season, so they must be studied independently.…”

Section: Observationsmentioning

confidence: 99%

“…In addition to direct effects of solar illumination, there is also interest in the indirect ways in which the Sun may control irregularity production in the ionosphere. It has been shown that negative IMF B z generally leads to higher echo occurrence in the auroral F region [ Ballatore et al , ]. Even stronger IMF control has been demonstrated for the auroral E region irregularities [ Makarevich et al , ].…”

Section: Introductionmentioning

confidence: 99%

Solar control of F region radar backscatter: Further insights from observations in the southern polar cap

Lamarche

Makarevich

2015

JGR Space Physics

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The role of solar wind and illumination in production of small‐scale F region plasma irregularities is investigated using a 4 year data set collected by the Super Dual Auroral Radar Network (SuperDARN) facility at the McMurdo station, Antarctica (MCM). Statistical analysis of ionospheric echoes detected by MCM shows that radar backscatter from the polar F region occurs in wide and persistent bands in range that exhibit systematic changes with local time, season, and solar cycle. It is demonstrated that all variations considered together form a distinct pattern. A comparison with the F region model densities and ray tracing simulations shows that this pattern is largely controlled by the F region solar‐produced ionization during the day. During the night, however, MCM observations reveal a significant additional source of plasma density in the polar cap as compared with the model. An example of conjugate radar observations is presented that supports the idea of polar patches being an additional source of ionization on the nightside. Echo occurrence exhibits a clear peak near the solar terminator, which suggests that small‐scale irregularities form in turbulent cascade from large scales. Further, echo occurrence is enhanced for particular interplanetary magnetic field (IMF) orientations during the night. Observations indicate that solar illumination control of irregularity production is strong and not restricted to the nightside. Indirect solar wind control is also exerted by the IMF‐dependent convection pattern, since the gradient‐drift instability favors certain orientations between the plasma density gradients and convection velocity.

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The influence of the interplanetary medium on SuperDARN radar scattering occurrence

Cited by 7 publications

References 13 publications

Effects of fast and slow solar wind on the correlations between interplanetary medium and geomagnetic activity

Effects of fast and slow solar wind on the correlations between interplanetary medium and geomagnetic activity

Seasonal and diurnal variations of PolarDARN F region echo occurrence in the polar cap and their causes

Solar control of F region radar backscatter: Further insights from observations in the southern polar cap

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