Solar Wind control of Auroral Kilometric Radiation as measured by the Wind Satellite

<p><span>Auroral Kilometric Radiation (AKR) emanates from acceleration regions from which escaping particles also excite a number of phenomenon in the terrestrial ionosphere, notably aurorae.</span><span> As such, AKR emission is a barometer for particle precipitation, indicating activity in the magnetosphere. Observations suggest that the emission is mostly limited to the nightside, relating to bursty tail reconnection events. In this study we investigate the relationship between upstream interplanetary magnetic field and solar wind conditions, and the onset and morphology of corresponding AKR emission. Additionally, we explore the delay time between the arrival of solar wind phenomena at the magnetopause, and the onset of related AKR emission and morphology changes. Connections between AKR and solar wind observations allude to solar wind driving of energetic particle precipitation at different local times. The WAVES instrument on the Wind satellite has provided measurements of radio and plasma phenomenon at a range of locations for over two decades, and in this study a recently developed method is utilised to extract AKR bursts from WAVES data, enabling quantitative examination of AKR emission over statistical timescales.</span></p>

Towards a Multi-Decadal Dataset of Auroral Kilometric Radiation (AKR) Source Parameters with Wind/WAVES

<p>Auroral Kilometric Radiation (AKR) is radio emission that originates in particle acceleration regions along magnetic field lines that coincide with discrete auroral arcs. Radio astronomy instruments aboard various spacecraft have been used to derive the flux density, source direction and other parameters of emissions of various origin. The Wind spacecraft has been in operation for 25 years and the WAVES radio instrument has previously been considered for a technique to also derive the Stokes parameters of a partially polarised radio source. While previous applications of the technique have seen it modified to study solar radio emissions, further examination is needed for its application to AKR. After correcting appropriately for the characteristics of the AKR emissions, this technique can be used to produce a utile dataset of AKR observations. Statistical properties of AKR can be examined, with the extent of local time sampling of Wind bolstering previous studies. The previously observed correlation between morphological changes in the source region and magnetospheric substorm onset can be studied further, and lists of substorm phase timings can be used to examine the general variability during these events.</p>

High frequency radio emissions as a manifestation of physical processes in the auroral plasma

<p>The Earth’s auroral region and its close neighbourhood is the origin of strong radio emissions caused by complex physical plasma processes. Among them we can list auroral hiss, auroral roar, auroral medium frequency (MF) burst, and auroral kilometric radiation (AKR).  Analysis of such emissions can provide information about magnetospheric structure and dynamics. </p><p>In this work we present selected cases of Earth’s AKR-like radio emissions observed by RELEC  and mission at the top side ionosphere leyers. The emissions are seen at frequencies of the order of hundreds of kHz in the ionosphere, just below the auroral oval and  can be observed not only in disturbed geomagnetic conditions, but also during quiet periods. The maximum occurrence is at ∼ 75 ◦ invariant latitude and can have extent up to ∼ 11 ◦ in invariant latitude.</p><p> </p>