Statistical study of ELF/VLF emissions at subauroral latitudes in Athabasca, Canada

Martinez-Calderon, Claudia; Shiokawa, K.; Miyoshi, Yoshizumi; Ozaki, Mitsunori; Schofield, Ian; Connors, Martin

doi:10.1002/2015ja021347

Cited by 21 publications

(29 citation statements)

References 37 publications

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“…While resonant wave-particle interaction appears to play a key role for the generation of diffuse/pulsating aurora precipitation as discussed above, some statistical studies using measurements at corresponding latitudes from Earth-orbiting satellites or ground-based instruments indicate that the wave activity is not uniformly distributed in MLT [e.g., Koons and Roeder, 1990;Meredith et al, , 2004Meredith et al, , 2009O'Brien et al, 2003;Martinez-Calderon et al, 2015]. Plasma sheet electrons can be scattered into the loss cone through resonant wave-particle interactions by electrostatic cyclotron harmonic (ECH) waves or whistler mode waves [e.g., Thorne et al, 2010].…”

Section: 1002/2016ja023484mentioning

confidence: 99%

Energetic electron precipitation and auroral morphology at the substorm recovery phase

et al. 2017

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It is well known that auroral patterns at the substorm recovery phase are characterized by diffuse or patch structures with intensity pulsation. According to satellite measurements and simulation studies, the precipitating electrons associated with these aurorae can reach or exceed energies of a few hundreds of keV through resonant wave‐particle interactions in the magnetosphere. However, because of difficulty of simultaneous measurements, the dependency of energetic electron precipitation (EEP) on auroral morphological changes in the mesoscale has not been investigated to date. In order to study this dependency, we have analyzed data from the European Incoherent Scatter (EISCAT) radar, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) riometer, collocated cameras, ground‐based magnetometers, the Van Allen Probe satellites, Polar Operational Environmental Satellites (POES), and the Antarctic‐Arctic Radiation‐belt (Dynamic) Deposition‐VLF Atmospheric Research Konsortium (AARDDVARK). Here we undertake a detailed examination of two case studies. The selected two events suggest that the highest energy of EEP on those days occurred with auroral patch formation from postmidnight to dawn, coinciding with the substorm onset at local midnight. Measurements of the EISCAT radar showed ionization as low as 65 km altitude, corresponding to EEP with energies of about 500 keV.

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Section: 1002/2016ja023484mentioning

confidence: 99%

Energetic electron precipitation and auroral morphology at the substorm recovery phase

et al. 2017

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“…They usually occur in the frequency range between about 0.5 and 4 kHz and the time separations between consecutive QP elements (modulation periods) can vary from some tens of seconds up to a few minutes (Carson et al, ; Manninen et al, ; Sato & Fukunishi, ). QP emissions are usually observed on the dayside (Engebretson et al, ; Hayosh et al, ; Martinez‐Calderon et al, ).…”

Section: Introductionmentioning

confidence: 99%

Dependence of Properties of Magnetospheric Line Radiation and Quasiperiodic Emissions on Solar Wind Parameters and Geomagnetic Activity

et al. 2019

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Very low frequency electromagnetic waves in the inner magnetosphere sometimes exhibit either frequency or time modulation. These phenomena are called, respectively, magnetospheric line radiation (MLR) and quasiperiodic (QP) emissions. Data from Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions spacecraft were used to analyze their properties, such as MLR frequency spacing, QP modulation period, and QP intensity as functions of geomagnetic activity and solar wind parameters. Altogether, 1,152 MLR events and 2,172 QP emissions were analyzed. It is shown that the influence of the analyzed parameters on QP emissions is different for QP events with modulation periods shorter/longer than 20 s. While the properties of QP events with long modulation periods are significantly related to the geomagnetic activity and solar wind parameters, no such dependences are observed for events with short modulation periods. This suggests that there might be two types of QP emissions generated by two different mechanisms. It is further shown that there seems to be no relation between the properties of QP and MLR events observed at the same times. Finally, the event properties do not seem to be related to the whistler occurrence rate.

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“…A great number of chorus observations have been performed both in space (e.g., Hattori et al, ; LeDocq et al, ; Li et al, ; Santolík, Gurnett, et al, ; Taubenschuss et al, ) and on the ground (e.g., Martinez‐Calderon, Shiokawa, Miyoshi, Ozaki, et al, ; Sazhin & Titova, ). However, to our best knowledge, the only observation of one‐to‐one correspondence between individual chorus elements detected on the ground and in space was reported by Jiříček et al ().…”

Section: Introductionmentioning

confidence: 99%

Conjugate Ground‐Spacecraft Observations of VLF Chorus Elements

Демехов

Manninen

Santolı́k

et al. 2017

Geophysical Research Letters

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We present results of simultaneous observations of VLF chorus elements at the ground‐based station Kannuslehto in Northern Finland and on board Van Allen Probe A. Visual inspection and correlation analysis of the data reveal one‐to‐one correspondence of several (at least 12) chorus elements following each other in a sequence. Poynting flux calculated from electromagnetic fields measured by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument on board Van Allen Probe A shows that the waves propagate at small angles to the geomagnetic field and oppositely to its direction, that is, from northern to southern geographic hemisphere. The spacecraft was located at L≃4.1 at a geomagnetic latitude of −12.4∘ close to the plasmapause and inside a localized density inhomogeneity with about 30% density increase and a transverse size of about 600 km. The time delay between the waves detected on the ground and on the spacecraft is about 1.3 s, with ground‐based detection leading spacecraft detection. The measured time delay is consistent with the wave travel time of quasi‐parallel whistler‐mode waves for a realistic profile of the plasma density distribution along the field line. The results suggest that chorus discrete elements can preserve their spectral shape during a hop from the generation region to the ground followed by reflection from the ionosphere and return to the near‐equatorial region.

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Statistical study of ELF/VLF emissions at subauroral latitudes in Athabasca, Canada

Cited by 21 publications

References 37 publications

Energetic electron precipitation and auroral morphology at the substorm recovery phase

Energetic electron precipitation and auroral morphology at the substorm recovery phase

Dependence of Properties of Magnetospheric Line Radiation and Quasiperiodic Emissions on Solar Wind Parameters and Geomagnetic Activity

Conjugate Ground‐Spacecraft Observations of VLF Chorus Elements

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