Multipoint visualization of ULF oscillations using the Super Dual Auroral Radar Network

Abstract

We present a technique for the automatic detection of Pc5 (150 s to 600 s period) ultralow frequency (ULF) pulsations in ground and ionospheric backscatter from the Super Dual Auroral Radar Network (SuperDARN). This new technique enables rapid identification and visualization of ULF oscillations over the very wide geographical coverage of SuperDARN. The technique detects ULF oscillations using the Lomb-Scargle periodogram method, which provides a natural test for periodic behavior against the null hypothesis of a pure noise distribution. This does not require any interpolation across data gaps and is thus appropriate for SuperDARN data. We demonstrate the application of the technique to SuperDARN data for March 2014 and find that Pc5 pulsations are frequently observed by multiple radars simultaneously. A preliminary investigation using data from all Northern Hemisphere SuperDARN radars indicates that Pc5 pulsation activity occurs most often on the nightside of the magnetosphere, with a mean frequency of about 2 mHz.

Conjugate Ionosphere‐Magnetosphere Observations of a Sub‐Alfvénic Compressional Intermediate‐m Wave: A Case Study Using EKB Radar and Van Allen Probes

“…The wave are observed as velocity variations of small‐scale field‐aligned ionospheric irregularities along the beam direction. The velocity variations occur due to the drift of the ionospheric plasma caused by magnetospheric ULF waves (Berngardt, ; Bland et al, ; Chelpanov et al, , ; James et al, ; Ponomarenko et al, , ; Wright & Yeoman, ; Yeoman et al, ). Due to the close arrangement of these beams the wave propagation direction and length can be determined.…”

First results of the high-resolution multibeam ULF wave experiment at the Ekaterinburg SuperDARN radar: Ionospheric signatures of coupled poloidal Alfvén and drift-compressional modes

“…Further in the paper we will study these Doppler drift variations of the scattered signal at distances 500-1500 km at night, not accompanied by simultaneous changes in the signal power, and which, as we assume, are related to the dynamics of E B × drift. Such a suggestion is usual for analysis of ionospheric scatter (Bland et al, 2014;Yeoman et al, 2000;Walker et al, 1992;Ponomarenko et al, 2003).…”

Survey of Ionospheric Pc3‐5 ULF Wave Signatures in SuperDARN High Time Resolution Data

“…The line‐of‐sight velocity measured by SuperDARN radars can be used to detect and monitor ionospheric ULF wave signatures with both high‐ and low‐ m (Fenrich et al, ; James et al, ) and with a total geographical coverage area that cannot be achieved with any other ground‐ or space‐based instrumentation. Based on a new data display technique developed by Ponomarenko et al (), SuperDARN‐detected ULF wave signatures have been characterized in a few recent studies (e.g., Bland et al, ; Norouzi‐Sedeh et al, ; Sakaguchi et al, ). These studies have been largely limited to the Pc5 range since SuperDARN radars are normally scheduled for 1‐min azimuthal sweeps in the common mode (e.g., Bland et al, ; Sakaguchi et al, ).…”