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HF radar signatures of the cusp and low-latitude boundary layer

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TLDR
In this article, an intercalibration study made using the Polar Anglo-American Conjugate Radar Experiment radars located at Goose Bay, Labrador, and Halley Station, Antarctica, and the Defense Meteorological Satellite Program (DMSP) satellites is used to provide clear identifications of the ionospheric cusp and the low-latitude boundary layer (LLBL).
Abstract
Continuous ground-based observations of ionospheric and magnetospheric regions are critical to the Geospace Environment Modeling (GEM) program. It is therefore important to establish clear intercalibrations between different ground-based instruments and satellites in order to clearly place the ground-based observations in context with the corresponding in situ satellite measurements. HF-radars operating at high latitudes are capable of observing very large spatial regions of the ionosphere on a nearly continuous basis. In this paper we report on an intercalibration study made using the Polar Anglo-American Conjugate Radar Experiment radars located at Goose Bay, Labrador, and Halley Station, Antarctica, and the Defense Meteorological Satellite Program (DMSP) satellites. The DMSP satellite data are used to provide clear identifications of the ionospheric cusp and the low-latitude boundary layer (LLBL). The radar data for eight cusp events and eight LLBL events have been examined in order to determine a radar signature of these ionospheric regions. This intercalibration indicates that the cusp is always characterized by wide, complex Doppler power spectra, whereas the LLBL is usually found to have spectra dominated by a single component. The distribution of spectral widths in the cusp is of a generally Gaussian form with a peak at about 220 m/s. The distribution of spectral widths in the LLBL is more like an exponential distribution, with the peak of the distribution occurring at about 50 m/s. There are a few cases in the LLBL where the Doppler power spectra are strikingly similar to those observed in the cusp.

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Citations
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Journal ArticleDOI

The response of the HF radar spectral width boundary to a switch in the IMF By direction: Ionospheric consequences of transient dayside reconnection?

TL;DR: In this paper, the authors used the Halley HF radar in Antarctica to study the equatorward motion of the spectral width boundary which appears to occur in response to a large change in the direction of IMF.
Journal ArticleDOI

On determining the noon polar cap boundary from SuperDARN HF radar backscatter characteristics

TL;DR: In this paper, the authors examined the boundary determined over 6 h of magnetic local time around the noon sector and its relationship to the convection pattern using four SuperDARN radars and found that it is consistent with approximately 1 keV ions injected from a subsolar reconnection site.
Journal ArticleDOI

A statistical study of the location and motion of the HF radar cusp

TL;DR: In this paper, a large-scale and continuous monitoring of the ionospheric cusp region offered by HF radars has been ex- ploited in order to examine the statistical location and motion of the equatorward edge of the HF radar cusp as a function of the upstream IMF BZ component.
Journal ArticleDOI

Spreading Speed of Magnetopause Reconnection X-Lines Using Ground-Satellite Coordination

TL;DR: In this article, the authors use conjugate Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft and Super Dual Auroral Radar Network (SuperDARN) radar measurements to observationally determine the X-line spreading speed at the magnetopause.
Journal ArticleDOI

Ionospheric signatures of split reconnection X‐lines during conditions of IMF Bz < 0 and |By| ∼ |Bz|: Evidence for the antiparallel merging hypothesis

TL;DR: In this paper, the authors present measurements of the convection electric field in the dayside ionosphere during extended intervals when the interplanetary magnetic field (IMF) has a negative Bz component and a significant By component (|By| ∼ |Bz|).
References
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Journal ArticleDOI

DARN/SUPERDARN : A global view of the dynamics of high-latitude convection

TL;DR: The Dual Auroral Radar Network (DARN) is a global-scale network of HF and VHF radars capable of sensing backscatter from ionospheric irregularities in the E and F-regions of the high-latitude ionosphere as mentioned in this paper.
Journal ArticleDOI

A new magnetic coordinate system for conjugate studies at high latitudes

TL;DR: In this article, the authors presented a variation on the corrected geomagnetic coordinate system that is well defined and smooth over the entire globe, and provided an analytic expression relating geographic coordinates, including altitude, to the magnetic coordinates.
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The frontside boundary layer of the magnetosphere and the problem of reconnection

TL;DR: In this article, Heos 2 plasma and magnetic field data obtained in the frontside boundary layers of the magnetosphere are presented, revealing that the low-latitude extension of the entry layer is of a somewhat different nature.
Journal ArticleDOI

The cusp and the cleft/boundary layer: Low-altitude identification and statistical local time variation

TL;DR: In this paper, the authors investigated the distinction between the low-altitude cusp and the cleft (with the latter identified as the ionospheric signature of low-latitude boundary layer (LLBL)) on both a statistical and a case study basis.
Journal ArticleDOI

Mapping the dayside ionosphere to the magnetosphere according to particle precipitation characteristics

TL;DR: In this article, a complementary approach is tried: regions are identified based on the plasma characteristics as observed by low-altitude satellites using an automated identification scheme applied to approximately 60,000 individual satellite passes through the dayside oval, probability maps are computed for observing various types of plasma precipitating into the ionosphere.
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